OF WASHINGTON. 21 
causes as those of our Rocky Mountain locust, i. <?., chiefly ex- 
cessive multiplication and want of fresh food. Throughout 
southern Europe, or at least large proportions of it, the month of 
July is apt to be excessively dry. I witnessed last year, early in 
July, in South France, a phenomenal occurrence of this butter- 
fly. Its larvae had absolutely devoured all the thistles and even 
the cultivated artichokes in those portions of the Midi which I 
visited, and I saw as many as 30 chrysalides upon a single grape- 
leaf in a vineyard adjacent to a railroad. The butterflies were 
excessively numerous along the lines of the different railroads, 
seeking in vain for fresh plants upon which to lay their eggs, and 
it is no wonder that under such circumstances they congregate in 
increasing numbers and finally rise in the air and travel such 
long distances, guided by the prevailing winds. What is true of 
this particular species is likewise applicable to some of the Yel- 
lows (genus Colias} . I shall never forget an experience on the 
morning of July 2d in training from Montpellier northward. As 
the train swept along it stirred up for many miles a continuous 
cloud of brown, yellow, and white butterflies, consisting chiefly 
of the species just mentioned and the common Pieris rapce. In 
reference to this last species it may perhaps be well to mention 
the successful introduction, here at Washington, of one of its 
chief parasites, the Apanteles glomeratus. 
Osten Sacken has recently called attention, in the Wiener 
Entomologische Zeitung, to the fact that P. J. StepanofT has 
published in Russian (Proc. of the Nat. Hist. Soc. of the Univ. 
of KharkofF, vol. xv) , an account of the parasitism of the larva 
of Systceckus leucophceus Meig. in the egg-sacs of Stauronotus 
vastator Stev. His observations seem to have covered also the 
years 1879 and 1880, the same period during which I was gradu- 
ally getting the truth as to the true character of the Bombyliid 
larvae infesting the egg-sacs of Caloptenus spretus. It will be 
remembered by most of you that Mr. J. Calvert, as subsequently 
appeared in the Transactions of the London Entomological So- 
ciety, was, during the same period, making similar observations 
in the Dardanelles. While the observations of Mr. J. G. 
Lemmon in California were subsequent to and instigated by my 
own (he having been employed by me to make observations 
and report on Cammila pellucida}* and our observations cannot 
