Mary Catherine Mize appeals from a jury verdict finding her guilty on all counts of a ten-count indictment charging her with misapplying and embezzling bank funds and making false bank entries. Because the government failed to prove that the defrauded bank was a "member bank of the Federal Reserve System," as specifically alleged in each count of the indictment, and the district court erroneously instructed the jury on this issue, we must reverse Mize's conviction, subject to reindictment and retrial.

In March 1984 a grand jury returned an indictment against Mize charging her with seven counts of embezzlement and misapplication of bank funds in violation of 18 U.S.C. Sec. 6561 and three counts of making false bank entries in violation of 18 U.S.C. Sec. 1005.2 The indictment charged that Mize, in her capacity as head teller at the Angleton Bank of Commerce (the "Bank"), made an unauthorized withdrawal from the savings account of one customer, wrote bogus checks to a fictitious payee on the checking account of another customer, and misappropriated numerous deposits of a third customer. The jury found Mize guilty on all ten counts, and the district court sentenced Mize to five years imprisonment followed by five years probation.

Each count of the indictment specifically alleged that the Bank was a "member bank of the Federal Reserve System." The government, however, did not prove this allegation. Instead, the government established that the Bank was insured by the Federal Deposit Insurance Corporation (FDIC). After the government's case-in-chief, Mize unsuccessfully moved for a judgment of acquittal. Her motion did not refer to any discrepancy between the indictment's reference to "member bank" and the government's proof of "insured bank." At the close of all the evidence, the district court instructed the jury that it should return a guilty verdict if, in addition to all other elements of the offenses, it found that the Bank was a Sec. 1005 "insured bank, as charged" and a Sec. 656 "national bank or an insured bank." Mize did not object to these instructions or renew her motion for a judgment of acquittal.

On appeal, Mize asks us to reverse her conviction because of the discrepancy between the language of the indictment and the evidence presented at trial and the language of the district court's instructions to the jury. As a general rule, once an indictment has been returned, its charges may not be broadened through amendment except by the grand jury itself. United States v. Young, 730 F.2d 221, 223 (5th Cir.1984). Although Mize made no objection at trial to the court's jury instructions, we may review this issue on appeal under the plain error doctrine because erroneous instructions concerning the essential jurisdictional element of the crime charged affect substantial rights of the defendant. United States v. Fitzpatrick, 581 F.2d 1221, 1223 (5th Cir.1978). Following the dictates of Stirone v. United States, 361 U.S. 212, 80 S. Ct. 270, 4 L. Ed. 2d 252 (1960), we must determine whether the discrepancy in this case constitutes a constructive amendment of the indictment, in which case reversal is required, or whether the discrepancy merely constitutes a variance between indictment and proof, in which case reversal is warranted only if the discrepancy has prejudiced substantial rights of Mize. See Young, 730 F.2d at 222. To resolve this question, we must determine whether the jury was permitted to convict the defendant on a factual basis that effectively modified an essential element of the offenses charged. If so, reversal is automatic because the defendant may have been convicted on a ground not charged in the indictment. Id. at 223; United States v. Ylda, 653 F.2d 912, 914 (5th Cir.1981).

Conviction under 18 U.S.C. Secs. 656 and 1005 requires proof that the defrauded bank was "any Federal Reserve bank, member bank, national bank or insured bank." These statutes each define "member bank,"3 which the indictment specified, and "insured bank,"4 which the government proved and concerning which the district court instructed the jury. The statutes' requirement of federally protected status for a bank serves a dual purpose, constituting both a jurisdictional predicate and an essential substantive element of the criminal offenses. See Young, 730 F.2d at 224; United States v. Trevino, 720 F.2d 395, 400-01 (5th Cir.1983); United States v. McRary, 665 F.2d 674, 678-79 (5th Cir.), cert. denied, 456 U.S. 1011, 102 S. Ct. 2306, 73 L. Ed. 2d 1307 (1982); United States v. Broome, 628 F.2d 403, 405 (5th Cir.1980). As we stated in Young: "if a federal offense may be predicated upon alternative bases of jurisdiction, a defendant's conviction cannot rest upon a basis of jurisdiction different from that charged in the indictment." 730 F.2d at 224.

Applying these standards to the instant case, we conclude that we must reverse Mize's conviction. Unlike the "unitary" jurisdictional statute involved in Young,5 the statutes involved in this case provide for two separately defined bases of jurisdiction: "member bank" status and "insured bank" status. Although the indictment alleged that the Bank was a "member bank," the government at trial proved only that the Bank was an "insured bank." Because of the language of the indictment, federal jurisdiction depended upon the government's establishing the Bank's status as a "member bank." United States v. Fitzpatrick, 581 F.2d 1221, 1223 (5th Cir.1978).6 Furthermore, the district court's instruction to the jury constructively amended the indictment by ignoring the "member bank" jurisdictional basis the indictment contained and adding the "insured bank" basis of jurisdiction. The failure of the government to prove the essential jurisdictional element of the charges against Mize and the district court's constructive amendment of the indictment at trial require us to reverse Mize's conviction. United States v. McRary, 665 F.2d 674, 679 (5th Cir.), cert. denied, 456 U.S. 1011, 102 S. Ct. 2306, 73 L. Ed. 2d 1307 (1982); Fitzpatrick, 581 F.2d at 1223. Like the Fitzpatrick court, however, we reach this result with great reluctance, for although Mize's guilt was established beyond a reasonable doubt, the inconvenience and expense of a retrial are now necessary.7

REVERSED.