510 ]\rr. T. D. A. Cockerell on new Insects 



nient of the coxa, trochanter, and femur strongly suggestive 

 of that pointed out by me in the case of the Phasmidte in my 

 communication to the Acaddmie des Sciences of February 15, 

 1897 *. I was particularly struck with this on examining 

 the last figure referred to, which, however, represents an 

 insect much more nearly allied to the Neuroptera than to the 

 Orthoptera, since M. Ch. Brongniart has assigned it to the 

 former. 



Messrs. Bateson and Brlndley, after mentioning numerous 

 instances of tetramery in Blattidaj, conclude that they are to be 

 regarded as cases of abrupt variation {^'variation bricsque^^), 

 explaining up to a certain point how a species with tetra- 

 merous tarsi might be derived, abruptly so to speak, from a 

 species with pentamerous tarsi (' Materials for the Study of 

 Variation,' 1894, pp. 63 and 415-421). A philosophical 

 explanation appears to me much more logical : this consists 

 in regarding, on the contrary, these interesting facts as cases 

 of atavism, of reversion to an ancestral condition similar to 

 that still to be observed in the Locustida3 1« 



LX. — Neio Insects from Emlnido, New Mexico. By T. D. A. 

 Cockerell, Entomologist of the New Mexico Agricul- 

 tural Experiment Station. 



As we ascend the E.io Grande the fauna and llora gradually 

 change, southern types giving place to others of a boreal or 

 sub-boreal character. The detailed study of the distribution 

 of species up and down the banks of the river presents much 

 to attract the zoologist or botanist, and the briefest investi- 

 gations are repaid by new and interesting results. The 

 present writer had recently an opportunity of spending a 

 couple of days at Embudo, situated on the Rio Grande in 

 northern New Mexico^ about 300 miles north of Mesilla. 

 This locality is in a district never explored by entomologists, 

 and it was to be expected that new forms would be found. 

 These expectations were not disappointed, and descriptions of 

 the novelties are herewith presented. 



Apidse. 



At the flowers of Bigelovia four species of Perdita occurred, 

 three of them in considerable numbers. They were as 

 follows : — 



* Vide supra, p. 476 : " Phenomena of Autotomy in Phasmidse 

 belonyiflg to the Genera Moncmdroptera and Rhaphiclerus.''' 



- 1 Cf. A. Giard, ' Comptes Reudus de la Societe de Biologie,' 1897, 

 no. 12, p. 315. 



