72 FIKST ANNUAL REPORT OF THE STATE ENTOMOLOGIST. 



tibiae in Boarmia, Tephrosia, and Acidalia, and on the submedian vein 

 of the forewing in some species of Macaria and Cidaria. 



Tiie particular effect produced by these odoriferous organs, is not 

 known, but from their being brought in action and extended like a fan, 

 during the union of the sexes, they doubtless serve an important purpose 

 in the economy of nature, by aiding in the continuance of the species. 

 It is not unlikely that attractive odors may be given to the males as a 

 compensation for the more brilliant coloring or more complicated or- 

 namentation often possessed by the other sex. 



Special odors pertaining to male butterflies, have been noticed by 

 several entomologists. Dr. Muller has called the attention of the 

 London Entomological Society to the odors of the males of several 

 species of Brazilian butterflies, which he regards as an especial sexual 

 attraction. Miss Murtfeldt has recorded a delicate violet like odor in 

 fresh males of Callidryas Euhule (not discoverable in the females), 

 which was i-etained for several days after death.* 



Tf, as we believe, insects have been given this acute sense of 

 smell, we may see in it a provision admirably adapted to their 

 need. Very many of the insects are night-fliers, sleeping or hiding 

 in concealment during the day, and only coming abroad during 

 the night to deposit their eggs and to partake of a limited supply of 

 food — the latter quite a secondary, consideration in their economy. 

 We have no reason to believe, from a study of their eyes, that vision in 

 insects is very acute, and even if it were, it would operate under serious 

 disadvantage under cover of the night. In utter darkness the organs 

 of smell could discharge their functions to their extreme extent — bet- 

 ter enabled, perhaps, to do so through the humid atmosphere of niglit, 

 and stimulated to their full exercise by the more numerous and 

 stronger odors which are emitted from the vegetable world during the 

 hours of darkness. 



And again, many insects must find their mates only through search- 

 ing them out under the seeming disadvantages environing the females 

 of limited locomotion, and a greater or less degree of concealment. As 

 a rule, the females fly less than the males. In some species, as in 

 Samia Cecropia, Callosamia Promethea, Hypercliiria lo, and others, the 

 burden of eggs borne by them render them almost incapable of flight, 

 until the main purpose of their being has been discharged. The females 

 of Orgyia leucodigma^ Anisopteryx poynetaria, A vernata, Hyhernia 

 Uliaria and a number of others, are wingless, and therefore incapable 

 of flight. In a moth quite destructive to arbor-vitse and many other 

 food-plants, Tliyridopteryx cpliernerwformis, or tlie basket-worm, the 



*/!s-y<:7/c, iii, 1881, p. 198. 



