ANTENNiE OF LEPIDOPTERA. 6 



I wish to ticknowlcd^t' my i:rcat indebtedness to Professor Com- 

 stock for his coustiint readiness with suugestioii and advice and for 

 the invahiable assistance lie iias given nie throngh his jjapers and by 

 personal conversations. I am also nnder obligations to Mr. Alex. 

 D. ]\IaeGillivray for tlic invariable kindness with wliicli he has aided 

 me in the work. 



For morphological study the antennae were removed from the head, 

 and, after dehydration in 95 per cent, alcohol and subsequent im- 

 mersion in clearer, mounted in Canada balsam. Each slide was 

 labeled with the name of the species, sex, and the side from which 

 the antenna w'as removed. The last item is of great importance, as 

 it enables the observer to determine the relative aspects in the subse- 

 quent study. 



For histological study the antenuai were removed with great cai'e 

 not to tear away the soft parts at the base. Some were fixed and 

 hardened with parts of the head still attached. The chitin f(n-ms A 

 dense covering over the softer parts, and it was possible to obtain 

 better results in the fixing and hardening, and especially in the in- 

 filtration with collodion, if the antenna was first cut into moderate 

 lengths so as to allow the fluids to work in from the ends. The 

 tissues were fixed in various fluids. The Pici-o-aceto-sublimate, de- 

 vised by Dr. P. A. Fish, gave the best results. It is composed of 

 fifty per cent, alcohol, lOOOcc. ; glacial acetic acid, 5cc. ; corrosive 

 sublimate, 5 grams ; picric acid, 1 gram. After immersion in this 

 fixer for twenty-four hours, the tissues were passed through '}0, 67, 

 82 and 95 per cent, alcohols and imbediled in collodion. The wlu)le 

 was cleared in the castor-thyme oil mixture* — red oil of thyme, 

 three parts ; castor oil, one part. Where exti-a thin sections were 

 desirable, the cut surface was painted with one per cent, collodion 

 before each section was made. This aided very materially in pre- 

 venting the tearing away of the softer parts from the tough chitin. 

 For staining, both Delafield's hematoxylin and the simple hema- 

 toxylin with a counter-stain of eosin produced excellent results. 



After considerable study of the natural attitude of the antennae 

 in live specimens, both in flight and at i-est, and also of the position 

 taken when the insect is killed and .-spread, the conclusion has been 

 reached that the normal position is assumed when the antenn;e are 

 extended directly laterad, with the most specialized surfaces ventrad, 



* A New Clearer for Col lud ionized Ohjei'ts, I\ A. Fish. Proc. Am. Micr. Soc. vol. 

 XV, pp. 86-89, 1H93. 



TRANS. AM. K.\T. SOC. XXIII. JANUARY, 1896. 



