88 



THE CANADIAN ENTOMOLOGIST. 



LARVAL CHARACTERS OF PACHYGASTRL/^ TRIFOLII AND 



AGLIA TAU. 



BY HARRISON G. DYAR, WASHINGTON, D. C. 



I have postponed replying to Mr. Bacot's communication (Can. Ext., 

 XXXV., 44-47) until I could examine his preparations. He has kindly 

 sent them to me, and they seem definitely to settle the two points 

 that remain at issue. The Ag/ia tau is in fluid, and shows a number of 

 secondary setas as described by Mr. Bacot. These setae are short 

 and unusually weak, so that in my own specimen, which is dried, inflated, 

 they had become partly shrivelled, partly broken in transit. I do not 

 think, after examining Mr. Bacot's specimen, that they can be regarded 

 otherwise than as true set*, and I am very willing to acknowledge myself 

 corrected. This correction, if applied to my synoptic table of Saturnian 

 genera (Tutt, Brit. Lep., HL, 272), makes my divisions stronger and 

 sharper than before, allying Aglia more strongly than ever with Attacus 

 and Saturn i a. 



The Pachygastria trifolii, in stage L, was new to me, but it shows 

 the normal structure exactly as I had anticipated. Tubercle v, which Mr. 



Bacot professes himself unable to find 

 any trace of, "single haired or otherwise,'' 

 is present in the normal position below 

 and before iv (see figure i). It is small 

 and single haired, but I see it distinctly 

 on several segments of the best-preserved 

 larva (in balsam on a slidej. The general 

 wart pattern corresponds with Mala- 

 cosoma, but the warts are more nearly 

 equal, ii, iii and iv not being reduced ; vi 

 is double, the halves well separated and 

 V distinct, while the secondary warts at the 

 anterior margins of the segments are well 

 developed. I do not anticipate that any 

 Lachneid will be found with tubercles 

 iv and v united. That condition is 

 uncharacteristic for the Bombycid phy- 

 lum, though it obtains commonly in the 

 Tineid lines. On this ground I would criticise Mr. Bacot's citation 

 of Anthrocera and Marasmarcha (Can. Ent., XXX V\, 45), which are 



Fig. 



