THE FLEAS OF NORTH AMERICA 55 



not known. Among the more recent figures of this species are those 

 by C. Fox (23, p. 138, fig. 65) and I. Fox (25 , pi. 20) . 



The rat flea, Nosopsyllus fasciatus, is of considerable importance 

 in the transmission of plague in certain countries. It is not a species 

 that bites man as readily as does Xenopsylla cheopis and is more 

 commonly found in temperate regions where plague is less likely to 

 be present. 



Bacot (1), in his extended studies on the biology of some common 

 fleas, gave us in 1914 facts as follows for Nosopsyllus fasciatus-. 

 Warmth (75° F.), combined with low humidity, favors the fertility 

 of the eggs. The newly hatched larvae were able to live in some 

 cases for over a month without food, provided the environment was 

 not otherwise unfavorable. According to Bacot there is a difference 

 in the kind of food necessary for fasciatus as compared with Pulex 

 irritans and Xenopsylla cheopis, the first mentioned apparently re- 

 quiring faeces of the adults as a necessity. The maximum duration 

 for the various stages of fasciatus was found to be u egg stage 10 days, 

 larval 114, cocoon 450, adult when fed 106, unfed 95/' 



Nosopsyllus londiniensis (Rothschild) 



Ceratophyllus londiniensis Rothschild, 1903, Ent. Rec. and Jour. Variation 15: 



64. pi. 3. 

 Ceratophyllus italicus Tiraboschi, 1904, Arch, de Parasitol. 8: 266, fig. 20. 

 Nosopsyllus londiniensis Jordan, 1933, Novitates Zool. 39: 77. 



Type host. — Mus musculus L. (house mouse). 

 Type locality. — South Kensington, London. 

 Range. — In North America known only from California. 

 The first record of the occurrence of this species in North America 

 was published by C. Fox (21, p. 11) in 1909. 



The Genus Trichopsylla Kolenati 



Trichopsylla Kolenati, 1863, Soc. Ent. Rossicae Horae 2: 32. Type, Pulev 



penicilliger Grube (by designation of Baker, 1904). 

 Malaraeus Jordan, 1933, Novitates Zool. 39 : 76. Type, Ceratophyllus telchinum 



Rothschild (by original designation). (New synonymy.) 

 Megabothris Jordan, 1933, Novitates Zool. 39: 77. Type, Ceratophyllus walkeri 



Rothschild (by original designation). (New synonymy.) 



Frontal tubercle small to vestigial, frequently partly contained in frontal 

 notch. Forehead usually with 2 or 3 rows of lateral setae, the upper or third 

 row, when present, usually not complete. Eyes present, pigmented, but fre- 

 quently reduced. Labial palpus short to medium in length, not extending 

 beyond apex of trochanter II. Pronotal comb with usual, long, dark spines 

 which are usually less than 24 in number. Femur I with several lateral setae; 

 coxa III without a row or patch of spinelets on inner surface ; inner surface 

 of coxae II and III with thin setae at most on distal half; last segment of 

 posterior tarsus with 5 pairs of lateral plantar bristles, the first of which may 

 be very slightly shifted or bent ventrally. Abdomen with a few apical spines, 

 all of which are dorsal or nearly dorsal in position. Tergal plate VII without 

 a posterior median process. Female with a single receptaculum seminis, the 

 head of which is variously shaped. Sternum VIII of male modified and fre- 

 quently bearing 1 or more setae; movable ringer of claspor with 1 or more 

 black, spinelike setae. 



Since the present writers recognize the first designation of the type 

 species of Trichopsylla by Baker (4) in 1904 as valid under the In- 

 ternational Rules, and this species, penicilliger Grube, is now in- 



