Nov. 1. 1919 European Corn Borer 177 



pale at the base, and the pale areas bordering the transverse antemedial and trans- 

 verse postmedial lines of forewing and in tlie postmedian region of hindwing lack the 

 bright ochreous hue of the male P. nubilalis. The yellow is quite as conspicuous in 

 the female, however. Beyond the cell in the forewing of both males and females 

 there is a conspicuous cloudlike blotch of grayish or ferruginous scales, which is much 

 less conspicuous in females of P. mibilalis and practically absent in P. ainsliei. It is 

 in genitalia characters, however, that the species is most easily and strikingly dis- 

 tinguished. The male genitalia are as figured (PI. 7, D); apex of tegumen rounded; 

 anellus without anellus lobes but with single, long, stout, ventrally projecting spur 

 (the "calcar"of Pierce)'; harpe without spines on inner margin of sacculus ; clasper 

 moderate; face of clasper somewhat irregularly oval. Female genitalia (PI. 8, C, D) 

 without strong chitinization anterior to genital opening; chitinized plates posterior to 

 genital opening pear-shaped, tapering anteriorly. Alar expanse of moths, 20 to 36 mm. 



The pupa has a very slightly produced front (PI. 9, B), not a decided knob like that 

 of P. aimliei but more uneven than that of P. nubilalis. The dorsal abdominal spines 

 are nearly obsolete and scarcely distinguishable; abdominal spiracles large, rounded, 

 oval; cremaster very stout and characteristic, broader than long (PI. 9, G); otherwise 

 as in P. nubilalis, except that cephalic end is somewhat more sharply tapering and 

 pupa is generally a trifle stouter; average length, 15 to 16 mm. 



The larva is easily distinguished from that of either P. nubilalis or P. ainsliei). 

 When full-grown it is 36 to 37 mm. long. The head is considerably larger and the mot- 

 tling of the head different, the darker pigmentation being in the form of groups of 

 small, distinct spots rather than splotches or continuous masses of blackish brown; the 

 ocellar puncture (C) of epicraniura lies postero-dorsad of ocellus VI rather tlian di- 

 rectly posterior to ocellus VI as in P. nubilalis and P. ainsliei; the mandible (PI. 1 1 , C) 

 is heavier, oblong rather than square; the median edge is straight or very slightly con- 

 caved , not outwardly angulated ; and the distal tooth concaved. Except when the parts 

 are greatly distended tlie shoulder of the stipes maxillaris has a decided hump which is 

 scarcely perceptible in the other two species (PI. 11, A, B). Crochets of prolegs are 

 rather stout and more evenly triordinal. 



DISTINCTIVE CHARACTERS 



The three species are very intimately related. In superficial adult 

 characters and in structure of the female genitalia P. ainsliei is most 

 readily distinguished. It lacks the sex scaling of the forewing, which is 

 such a prominent character in P. nubilalis and P. penitalis. On the other 

 hand P. ainsliei and P. nubilalis are most alike in structure of the male 

 genitalia and hardly separable in larvae, while P. penitalis is readily dis- 

 tinguishable from the other two in both. The adult male of P. mibilalis 

 is easily distinguished from all American species of Pyrausta by its dark, 

 smoky, fuscous forewings and hindwings combined with the distinctly 

 yellow color of the lighter areas. 



' Pierce, F. N., the gbnitaua of the brjtish ceometkidam. 88 p., 48 pi. Liverpool, 1914. 



