BUTTERFLIES OF THE DISTKICT OF COLUMBIA 43 



which as a rule are abundant, were not so very common. No individ- 

 uals of the spring brood of either species of Basllarchia were seen. 



The summer of 1030 was hot and very dry. At the end of the sea- 

 son the scarcity of butterflies was very noticeable. Such common 

 species as Colias philodlce, Eurema Usa, Eveves comyntas, Fhyciodes 

 tharos, and Ancyloxypha nmnitoi- were represented by scattered indi- 

 viduals only, and nearly all the other species were correspondingly 

 scarce. Colias eurytheme seemed to have suffered less than the other 

 common butterflies, and was far more numerous than C. fMlodice. 

 It was noticed that all the individuals captured, and so far as could 

 be judged all that were seen, were of the keewaydiri or intermediate 

 form. No examples of either the very light ofnadne or the deeply 

 colored eurytheme form were found. 



Of the skippers the most numerous in all suitable localities was 

 Erynnis Jeonardus^ which usually is very much less common than 

 Atalopedes campestrls^ Polites coras^ P. cernes, Ancyloxypha numi- 

 tor, and Epargyretcs tityttis — this last late in the summer of 1930 was 

 exceptionally scarce and was represented only by very few much- 

 worn individuals. 



Of the sAvallowtails the commonest was Papilio glaueus, though P. 

 troilm was almost as common; P. philenor, which is usually by far 

 the commonest swallowtail at this season, was scarce and all the indi- 

 viduals were small or very small; P. polyxenes was very rare, and 

 P. inarcellus was not found at all. 



The numbers of the fritillaries {Argynnk idalia, A. cybele, and 

 Euptoieta claudia) seemed to be normal for the season. 



The relative abundance of Papilio glaucus^ the actual numbers of 

 which seemed to be no greater than usual, is probably explained by 

 the fact that this species is here chiefly, or perhaps even entirely, a 

 tree feeder, and trees are less affected by drought than are the shrubs, 

 vines, and herbaceous plants upon which the other swallowtails feed 

 as caterpillars. 



EryTmis leonard^m is a species confined to more or less permanently 

 wet areas and is therefore the least likely of the late-summer skip- 

 pers to be affected by drought. 



The relative abundance of Colias eurytheme probably was mainly 

 the result of the increase to be expected in a recently acclimated 

 species especially well adapted to dry conditions. 



The spring of 1931, up to June 1, was mainly devoted to a study 

 of the woods and fields in the vicinity of the lowest of the bogs 

 along Paint Branch. 



On April 29 Incisalia augustinus and /. mphon were found to be 

 rather common here; AnthochaHs genutia and Lycaenopsis argiolus 

 were more numerous than I have seen them elsewhere in this region ; 



