March, 1913.] PROCEEDINGS OF THE SOCIETY. 87 



herbarium specimens, Eois ptelearia, as an example of the driest kind of food 

 for Lepidoptera. 



Mr. Davis, referring to Prionaptery.v nebulifera, said that it occurred also 

 at Yaphank, thus extending its previously known range. 



Dr. Forbes spoke of the coloration of the forms of arid regions being dis- 

 tinctive, citing Hemileuca tricolor as a typical desert form and the bleached-out 

 forms observed in other desert regions, and Etixoa detorsa, Porosagrotis ve- 

 tusta, etc., common in the pine barrens and dominant in light clay-colored 

 forms. Hypantria ciinea, the fall web-worm, has a variety, pallida, which pre- 

 sents similar coloration, making its habits worth discovering. Speaking of 

 structures for breaking through baked ground and dense cocoons. Dr. Forbes 

 said that while he had never seen it done the fact that such structures were 

 infinitely more numerous in species of arid regions and present in fifty to sixty 

 per cent, of the species of Australia were certainly suggestive. He had pre- 

 pared a list of genera in which this structure was present, and he showed a 

 microscopic mount of the leg of Lygranthwcia thoreaui, in which the climax is 

 reached in a flattened tibia provided with six broad flattened spines, forming a 

 most efficient digging tool. 



Mr. Olsen mentioned Miitilla as a characteristic insect of dry places. 



Dr. Osburn said that neither dragonflies nor Diptera could well belong to 

 a xerophytic classification, on account of the larval life being either aquatic 

 or spent in sucking juices. He mentioned certain Syrphidae burrowing in 

 cactus, Volucella fasciata in particular. 



Mr. Dow stated that Lasioderma serricorne preferred to chew the driest 

 tobacco, and the wonder was how it could raise enough saliva to spit out the 

 juice. 



Dr. Lutz, criticizing the preceding speakers and particularly Mr. Leng, said 

 that individual species of plants as well as insects were often found in strange 

 environments, and it had been the endeavor of botanists to show that while 

 this was true of individual species it was never so with the societies of species 

 found associated in certain environments ; and such he expected would also 

 prove true of insects. He expressed his gratification at the number of special 

 adaptations for dry environment disclosed by the evening's discussion, and sug- 

 gested that the number might well be increased when the subject had received 

 further study and certain orders not yet touched upon were considered. He 

 agreed with Mr. Leng that in the case of insects factors not considered by bota- 

 nists would prove of importance, especially food and light, but he doubted if 

 the wilful behavior of insects would be found strongly operative. In the matter 

 of light he cited especially his own experiments with Drosophila and stated that 

 their utter inability to avoid flying towards the light was indisputable. 



Mr. Davis and Dr. Lutz discussed the case of Gryllus abbreviatus and the 

 disputed relationship between it and G. pennsylvanicns. 



Dr. Forbes spoke of the black and green forms of the pursley worm, 

 Deilephila lineata, green when feeding in a tree endwise to the sun with air 

 blowing all around it, black when on bare ground without shelter from the sun. 



