June, '19] MOSHER: EUROPEAN CORN AND OTHER BORERS 265 



individuals show it with an emargination as in nubilalis (Fig. 13, no. 31) 

 and less often with the sharper eephalo-lateral angle usually found in 

 that species. The anterior dorsal setae (setse I) on the eight abdominal 

 segments are, like most of the setse, situated on dark tubercles which 

 are often almost contiguous in genitalis, separated by a distance usually 

 much less than the width of the tubercle, while the distance is usually 

 much greater in nubilalis, but these vary somewhat. Another useful 

 character, if its variations could be well described are the clear areas 

 of the abdominal segments. These are shown contrasted in Fig. 13, 

 nos. 27 and 28 and again in Fig. 13, nos. 31 and 32. These are always 

 very distinct on each side of the median line on abdominal segments 

 2-8 in penitalis, each space oval, and nearly every space well bounded 

 and separated from the next one, so as to give a row of them a distinctly 

 moniliform appearance. Segments 3-7 usually show these rows of 

 spaces divided into two sections, near the middle of the row, the space 

 between varying in different segments (Fig. 13, no. 28). While these 

 spaces may vary slightly as to number or degree of separation between 

 individual spaces, there is a remarkable uniformity in all the segments. 

 This is never true in nubilalis. After studying a large series of speci- 

 mens, nothing approaching the regularity of penitalis was discovered. 

 This species seldom shows anything but an irregular clear strip, but 

 occasionally the spaces on one or two segments will seem to be quite dis- 

 tinct, but this arrangement will be different on other segments. The 

 arrangement of spaces in nubilalis is shown in Fig. 13, no. 27 and they 

 are seldom more distinct. When a skin is cleared and mounted the 

 clear spaces in penitalis remain unchanged, while the nearest approach 

 to this arrangement in nubilalis showed only a clear band, with no 

 subdivision into individual spaces. There is a prominent furrow cau- 

 dad of the anterior tubercles in penitalis, ending at the sensory pore. 

 In nubilalis there are many more clear spaces in this location. 



The setal arrangement on the head varies in the two species. The 

 anterior setae and punctures (ant. 1, 2 ant. P) have a very constant 

 arrangement. In penitalis (Fig. 13, no. 30) they are not in Une, the 

 second seta being farther laterad than the first seta and the puncture. 

 In nubilalis the setae and puncture are nearly in line, with the puncture 

 a little laterad. The adfrontal setie and punctures offer some help 

 in determination, their position in penitalis being fairly constant, with 

 the second adfrontal always below seta P (Fig. 13, no. 30). The setae 

 in nubilalis are more variable in their arrangement, being sometimes 

 much like penitalis with the second adfrontal ()j)posite seta P, rarely 

 below it. In many individuals they are as far dorsad as in Fig. 13, no. 

 29 which represents the extreme in that direction. 



The skin sculpturing is of some iielp, Ix'ing a|)iKir(>ntly very constant 



