878 



AN INTRODUCTION TO ENTOMOLOGY 



parts with a somewhat flexible articulation between the-n. (Fig. 



1124); the anterior part bears the mouth-parts and the eyes, while 



the antennae are joined to the 

 posterior part. The falx (Fig. 

 1 12 2, /), which is present in 

 many of the more specialized 

 fleas is evidently a vestige of 

 the articulation between the 

 two parts of the head; even 

 this vestige is wanting in many 

 fleas. 



The mouth-parts are form- 

 ed for piercing and sucking. 

 When seen without dissection 

 these parts are apparent: the 

 maxilla, which are triangular 

 plates (Fig. 1122, mx)\ the 

 maxillary palpi, which are long 

 and four-jointed (Fig. 11 22, 

 mx. ;p); and the proboscis, (Fig. 

 1122, p). 



The proboscis consists of an 

 elongated labrum-epipharynx, 

 two long and slender mandi- 

 bular blades, and a sheath 



formed by the labiimi and the labial palpi. The space between the 



labrum-epipharynx, in the lower side of which there is a groove, 



Fig. 1 1 22. — Head of a flea, Cer atophyllus 

 multispinosus : j, falx; mx, maxilla; 

 mx.p, maxillary palpi; p, proboscis. 

 (After Baker.) 



Fig. 1 123.— Antenna of fleas: 

 A, Ctenocephalus felis; B, Cer- 

 atophyllus fasciatus. (After Pat- 

 ton and Cragg.). 



Fig. 1 1 24. — Head and prothorax of 

 Ischnopsyllus: F, frons; O, occi- 

 put; N, pronotum; P, propleurum; 

 a, antenna; c, ctenidia; m, maxilla; 

 mp, maxillary palpus. 



and the mandibular blades, which are closely applied to the lab- 

 rum-epipharynx, serves as a food-canal, through which the blood 

 taken from the host is sucked into the alimentary canal. There is 

 also a second canal formed by the apposition of two grooves, one on 

 the inner side of each of the mandibles; through this canal the 

 salivary secretion is forced into the wound. The piercing organ is 

 the mandibles; the distal part of each mandible is beset with re- 

 curved teeth ; and the proximal end of the blade is connected with a 

 chitinous lever, which in turn articulates with the head-capsule; by 



