94 



SIXTH ANNUAL REPORT 



oi' food-plant, weve grata or nnio — and "distinguishable" to me means the ability so to 

 do. I have long since learned to value a short and comprehensive description, which 

 covers the characters of many specimens, above one which deals too much in variable 

 details of fewer specimens. As already stated, the spots and stripes are so variable in 

 grata that individuals placed alongside of the two unio larvfe, loaned me, were abso- 

 lutely undistinguishable in these respects, and answer, in every point, to Mr. Lintner's 

 description of z««io. Size, while specifically a good criterion in full grown specimens, 

 even where the difierence is no greater than in these two species, is of little value in dis- 

 tinguishing individuals, as 1 have a captured unio imago larger than some gratas. 

 Length of hairs from the black spots.is likewise of jio value whatever, as the relative 

 length is the same in the two species. Indeed the length of these hairs alone would not 

 distinguish Eudryas from Alypia, for while those of the latter are longer in the young 

 larva, they are as described further on, when it is full grown. There consequently 

 remain no constant differences between the larv;r^ of grata and tmlo, except the 

 smaller anal hump, the lateral yellowish shade which "rests on the incisures, " as 

 described by Mr. Lintner, but which I did not notice in the alcoholic specimens, and 

 the greater paleness medio-ventrally in the latter. 



Unless, therefore, the living unio larva presents characteristics not noticeable in 

 the alcoholic specimens, I would not undertake to specifically determine an individual 

 with any confidence, however easily and confidently the two may be distinguished 

 when full grown and in large numbers on their respective plants. 



4. THE EIGHT-SPOTTED FORESTER— ^ ;?/;;*« oetomaculata, Fabr. 

 (Ord. LEPiDOrxKRA ; Fam. Zyg.exid.e.) 



This worm (Fig. 25, a) though resembling 

 the two preceding in being marked witli 

 orange bands across the middle of the 

 joints, may be at once distinguished by 

 having eir/hi (Fig. 25, h,) instead of six 

 black stripes to the joint, and by having a 

 series Of lateral white sub-stigmatic spots. 



Alypia octomacui.ata — Larva. — Average lengtli, 



when full grown, 1.30 Inch. Of same form as Eu- 



i^dryas. Ground color white, marked transversely 



with 8 black stripes to each point, and a broader 



Alyi'ia octojiaculata:— (7, invva; b, orange band, bounded by the two middle stripes, 

 enl.arffed ioiut, t^iUc \iew; c, I'e- , . , ,, . . . -, , ■, i- • ^ 



male moth. which are generally mterrupted ; orange band famt 



on joints 2 and 3, or sometimes quite obsolete ; conspicuous on 4 and 11 ; uniform on 

 intermediate joints. In the middle joints each orange band contains eight black coni- 

 cal, elevated spots, arranged in two rows, each spot giving rise to a white hair, seldom 

 longer than the width of the band. These spots are arranged as in the enlarged sec- 

 tion shown in the engraving (Fig. 25, &,) name!}', four on each side, as follows : the 

 xipper one on the anterior border of the orange band, the second on its posterior bor- 

 der, the third just above the spiracle on its anterior border — each of the three interrupt- 

 ing one of the transverse black lines— and the fourtli, which is smaller, just behind the 

 spiracle. The anterior dorsal spots on joints 4, 5 and 0, and tlie posterior ones on 11, 

 considerably larger than the rest. Head and cervical shield, shinj'^, deep orange, witli 

 black piliferous spots. Venter black, slightly variegated witli bluish-white, and with 



