277] NOCTUID LARVAE— RIPLEY 35 



Altho the extent of variation in the larvapods of noctuids does not 

 approach that which Goosen's series of these appendages reveals in the 

 entire order, they differ quite markedly in form, number, relative size, 

 number of crochets, and amount of chitinization. The setal arrangement 

 is practically uniform. As previously stated, from two to four pairs of 

 median larvapods may be present, the first one or two pairs, which are 

 located on the third and fourth abdominal segments, being absent in 

 certain groups. In the Phytometrinae the two cephalic pairs are usually 

 wanting, altho Hampson mentions one genus whose larvae have the full 

 number. The Catocalinae exhibit a pronounced tendency toward the 

 reduction of the first two pairs, which reaches its acme in Caenurgia, where 

 they are entirely absent. The first pair only are generally lacking or 

 without crochets in the Hypeninae. According to Hampson, the Eras- 

 trinae also bear but three pairs of median larvapods, altho the larva of 

 Chamyris cerintha, which was evidently unknown to him, has the full 

 number, the first pair being as well developed as the rest. The larvae of 

 other subfamilies of which material has been available for study are pro- 

 vided with four pairs of median larvapods with the first two pairs usually 

 not strikingly smaller than the others. In certain Phytometrinae the 

 vestiges of the lost larvapods can be discerned as heavily chitinized small 

 protuberances bearing the setae in about the same position which they 

 occupy in the fully developed appendage. Epizeuxis luhricalis of the 

 Hypeninae has the first pair fairly well developed but completely lacking 

 crochets. The number and relative size of the larvapods furnish very 

 fundamental characters, altho no noctuid subfamilies can be reliably 

 diagnosed upon this basis alone. 



Since the caterpillars of the most generalized famihes and of the great 

 majority of all Lepidoptera bear four well developed pairs of median 

 larvapods, this is most reasonably regarded as the generalized condition. 

 Their reduction has taken place in a few very distantly related groups, this 

 process having proceeded to a different extent in each. In the Cochlidiidae 

 they are entirely absent and in the Geometridae only the last pair of 

 median ones and those of the anal segment persist. Certain groups of 

 Noctuidae, apparently represent an incipient stage in this process of reduc- 

 tion, as exemphfied by the Agrotinae, in which the first two pairs are typi- 

 cally somewhat smaller than the rest. In the Catocalinae the same ten- 

 dency is exhibited to a much greater degree. The Phytometrinae and 

 Hypeninae, whose larvae are generally the most highly specialized in the 

 family in this respect, are placed by Hampson among the most specialized 

 noctuids on the basis of the structure of the adults, whereas the larvae of 

 the Acronyctinae, which he regards as a relatively generalized subfamily, 

 always have the full number of larvapods well developed. 



