PSYCHE. 



247 



geographical barriers due to geologic 

 or climatic changes, come to be distinct 

 species — species often distinguished 

 only by superficial differences in color 

 and markings of plumage, etc. The par- 

 asites have remained practically unaf- 

 fected by the conditions which have 

 produced the differences among the 

 birds; the temperature of the host's 

 body, the feathers as food, all of the 

 environment of the parasite is practically 



unchanged. The parasitic species thus 

 remains unchanged, while the ancestral 

 Larus or Anas species becomes differ- 

 entiated into a dozen or score of specific 

 forms, all with a common parasite. If 

 this proposed solution of the problem 

 may be accepted, it introduces a factor 

 into problems of distribution, where 

 parasites are concerned, which I do not 

 recall having seen presented before. 



NOTES ON NEW ENGLAND ACRIDIIDAE, IV,— ACRIDIINAE, I. 



BY .'ALBERT P. MORSE, WELLESLEV, MASS. 



The New England species of Acridii- 

 nae or spine-breasted locusts are readily 

 recognized by the presence of a promi- 

 nent spine or tubercle projecting from 

 the prosternum between the bases of the 

 anterior pair of legs. Sixteen species 

 of this sub-family have been taken in 

 New England ; one of these, however, 

 Schistocerca americana, being of purely 

 adventitious occurrence. Those that 

 form the fauna proper to the district 

 fall into two groups : two species of 

 Schistocerca, and thirteen species of 

 Melanopli. The former genus is at 

 present undergoing revision by Mr. 

 Scudder ; the latter group forms the 

 subject of his monumental " Revision of 

 the Melanopli " (Proc. U. S. Nat. Mus., 

 vol. XX, pp. 1-42 1 ) to which the student 

 is referred for a general discussion of 

 the group, for systematic characters, 



and information concerning its extra- 

 limitally. 



I have adopted here the sequence of 

 genera and species given in that work, 

 preceded by Schistocerca, as follows : 

 Schistocerca (3 sp.), Hesperotettix (i 

 sp.), Podisma (i sp.), Melanoplus (10 

 sp., in this order, — at/anis, sacdderi, 

 mancus, fasciatus, femitr-rubrum, extrem- 

 us, minor, collinus, femoratus, pitnctnla- 

 tus), and finally, Paroxya (i sp.). The 

 student dealing with specimens from 

 New England or the northeastern States 

 alone, however, will find a different ar- 

 rangement of his collection preferable, 

 e. g., the following: — Schistocerca (3 

 sp.), Paroxya, Hesperotettix, and Podis- 

 ma (each monotypic in New England), 

 and ■ finally Melanoplus, in this order : 

 manais, scudderi, ailanis, femnr-rubrum, 

 extrcmtts, fasciaius, minor, col/iniis, ptmc- 



