66 Journal of Entomology and Zoology 



Crolalus mildifUi (Cope). 



This specimen was collected by Dr. Hilton ami Dr. Miinz of Pomona t'ollepc, at 

 Forest Home, San Bernardino Mountains, June ", 1919. 



Crolalus ifraslfs (Hallowell). 



One specimen taken at Needles, California, April 1, 1920. These snakes seem to 

 be almost rniircly restricted to the sandy areas of the desert, rarely wandering from 

 them, and then only for a short distance, its mode of locomotion admirably fits it for 

 the tvpe of country which it inhabits. The ordinary snake finds difficulty in rapid 

 motion over the loose and shifting sand, since part of the tractive power comes from 

 a bracing of each loop of the body against that part of the ground which is posterior 

 to the loop, and through the movement of the central portion of the body against 

 the surface of the ground. It can readily be seen that a shifting and loose surface 

 would seriously hinder the progress of the ordinary snake. The "Side-winder," 

 Crolalus teraiirs, instead of progressing as do ordinary snakes, longitudinally, pro- 

 gresses laterally, leaving separate tracks, each paralleling the other, and angling in the 

 direction in which the snake is moving. Each track is approximately the length of the 

 snake making it, and is wavy, that is, a series of "S" shaped loops. The tracks 

 give no sign of any part of the body moving from one mark to the other, which gives 

 the impression that the snake jumps the 3 to 6 inch interval between the tracks. Such is 

 not the case, however. When the snake is moving, the body is kept partially looped 

 and the advance seems to he through the advancing of the head and tail, while the 

 rest of the body is rested on the intervening loop, supporting the rest of the body, 

 the weight then seems to be shifted to the head and tail and the rest of the body 

 advanced, the whole progression being a series of graceful and contiiuiors movements. 

 This sterns to be the mode of progression. 



Crolalus alrnx (Baird and Ciirard). 



Taken at Mecca, California, April 4, 1920. Foiuid in ilic arrow w;.'ed where 

 it seemed to be fairly common. 



In addition to the above list of specimens from the desert region there remain 

 that from the vicinity of Claremont, California, which is as follows: i'la slanshuriana 

 htsfteris, Richardson; Sielufiorus oiiiJentalis hi-sfrialus, Hallowell; I'/irynosoma 

 blainvillii hlainvillii, Ciray; Gerrlionolus scinc'uauda txfhhii, Baird; .Innitlla fulclira 

 puldira, (tray; .Innirlla (iluchra nigra, Fisher( doubtful location. Specimen not 

 labeled. Another from Laguna Beach August 1, 1920) ; Cnrmidopliorus ligris slej- 

 iiff/rri. Van llenburgh; I'lrsliodon skillonianum. Baird and Girard; l.iclianura rose- 

 ojusca. Cope (two taken from vicinity of Claremont and one from east of Victorville 

 by \V. M. Pierce); Tliamnnfiliis nnlino'iiles hamonJii. Kennicott; OiaJnf'liis amahitis, 

 Baird and (Jirard; l.nmfrnpfltis pyrnmrlana inultiiincia. Yarrow; l.amprnprllis 

 lioylii, Baird and (iirard; R/iinoi hrihis Irconlei, Baird and Ciirard; llypsiglena 

 orlirorhyndius. Cope; Salvadora liexalefiis, Cope (taken in Imperial Valley 10 miles 

 cast of Holtville) ; Coluhrr eonslrirlor vfluslus, Baird and Girard; Coluhfr flagellum 

 frrnalus, Slejneger; Coluhrr lalrralis, Hallowell; P'lluopliis tatrniffr ralrniffr. Blain- 

 vllle; Crolalus orrganus, Holbrook. 



