OF WASHINGTON. 407 



A PARALLEL EVOLUTION IN A CERTAIN LARVAL CHARAC 

 TER BETWEEN THE SYNTOMID^E AND THE 

 PERICOPID^E. 



By HARRISON G. DYAR. 



It has been fully pointed out that the larva? of the Syntomidae 

 have but a single wart on the meso- and metathorax above the 

 stigmatal wart. This wart is formed from primitive tubercles 

 ia, ib and iia, iib not forming a wart and being often discernible in 

 the mature larva as a single hair. This character persists in all the 

 Syntomid larvae examined so far, though the hair clothing may 

 vary from abundant tufts to single hairs, and the shape and size 

 of the warts may vary equally. This single wart occurs in no 

 other family (except as I will point out), at least in the same 

 way. Occasionally one of the two normal upper thoracic warts is 

 lost by becoming small and finally obsolete, but this is a dif 

 ferent thing from the single wart formed by coalescence. In the 

 Pericopidas, however, this structure has been paralleled. The 

 Pericopidae are not very closely related to the Syntomidae. The 

 moths stand somewhat below the Arctiidse and the larva? seem to 

 have likewise evolved separately, with an independent wart 

 formation, probably from near the Dioptidas. I have already de 

 scribed the beginning of coalescence of the upper thoracic warts 

 in the larva of Composia fidelissima ; the following descriptions 

 will show the completion of this process and also review the 

 larvae of the North American genera. 



Genus Daritis Walk. 



Daritis howardi Hy. Edw. Mr. Cockerell has twice sent me 

 (base of Organ Mts., New Mexico) larvae which I am inclined 

 to refer to this species, although they reached me in too weak a 

 condition to allow of their being bred. They appeared as fol 

 lows : Large, apparently strong and active, with large head and 

 well developed normal legs. Irregularly banded, black and oche- 

 rous, the hairs sparse, arising from large warts with tufts of short 

 dense hair from some, the others polished, blue-black or ocherous. 

 In detail : Head large, not bilobed, flat before, the sides sloping ; 

 clypeus slightly depressed, its sides contracted, the paraclypeal 

 pieces reaching not over half way to the vertex ; antennae mod 

 erate ; ocelli distinct except the fifth (from above), which is very 

 small ; all jet black, polished, the epistoma and basal joint of 

 antennae and palpi white ; width nearly 6 mm. Thoracic feet 

 large, shining black ; body uniform, joint 12 scarcely perceptibly 

 enlarged ; feet large, with densely hairy plates and well developed 

 claspers of the Macro type. Warts large ; on pro thorax the 



