1891.] ENTOMOLOGICAL XEtt'S. 133 



Hydroporus vi'/is and Agabus lugens, with occasionally an exam- 

 ple of some rarer forms, and on the banks a number of Bem- 

 bidium mexicanum, a not particularly agile species in that climate. 

 The spot was left with considerable regret, though a scarcity 

 of provisions in the commissary department made this more nec- 

 essary, and if the specimens were not so numerous as might be, 

 they were of sufficient interest to more than compensate for any 

 failings in point of numbers. 



o 



Notes on Colias csesonia. 



By Prof. R. R. ROWLEY, Curryville, Mo. 



Although c<zsoyiia is the rarest species of Colias in Missouri, 

 yet it is fairly common some years, especially in localities where 

 its food-plant is abundant. Toward the latter part of May I have 

 taken numbers of it at red clover blossom in July, and August at 

 thistle and milk-weed blooms, and late in Autumn on the flowers 

 of red and white clover. It is as easily taken as Philodice or 

 Eurytheme, with both of which it associates at flowers, but unlike 

 the males of them, it never frequents damp places, so far as my 

 observations go. 



The flight of this butterfly is not noticeably different from that 

 ot our other two species of Colias, yet the experienced collector 

 is able to detect it on the wing among numbers of other Coliads, 

 even at a considerable distance; the very broad and intensely 

 black border, outlining the peculiar " dog's head" on the top of 

 the primaries, together with the pointed apex of the same wings, 

 doubtless aiding most in the identification. At rest, the roseate 

 undenvinged females of October may be known a hundred yards 

 away in a clover-field. The females of the early and midsummer 

 broods differ from those of late Summer and Autumn in the very 

 pale yellow, almost white, color of the underside of all the wings. 

 In August this pale yellow deepens, and in early September red- 

 dish streaks appear along the veins of the hind wings beneath, 

 while in October the entire under surface of the secondaries and 

 the tip of the primaries are heavily streaked or solidly red. The 

 broad outer border of black in some females contains a few, more 

 or less distinct, yellow spots, as we see in the female Enrytheme 

 or Philodice, but a majority of the individuals entirely want these 

 spots, although the border is much less intense than in the males. 



