878 



AN INTRODUCTION TO ENTOMOLOGY 



parts with a somewhat flexible articulation between them. (Fig. 



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



the antennae are joined to the 

 posterior part. The falx (Fig. 

 1 122, /), 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 

 maxillae, which are triangular 

 plates (Fig. 1122, mx); the 

 maxillary palpi, which are long 

 and four-jointed (Fig. 11 22, 

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

 1 1 22, p). 



The proboscis consists of an 

 elongated labrum-epipharynx, 

 two long and slender mandi- 

 bular blades, and a sheath 



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



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



Fig. 1122. — Head of a flea, Cetatophyllus 

 multispinosiis : f, falx; mx, maxilla; 

 mx.p, maxillary palpi; p, proboscis. 

 (After Baker.) 



Fig. 1 1 24. — ^Head and prothorax of 

 Ischnopsyllus: F, frons; O, occi- 

 Fig. 1123.- Antennce of fleas: put; N,pronotum; P, propleurum; 



A, Ctniocephalus felis; B, Cer- '^-antenna; c, ctemdia; m, maxilla; 



atophyllusfasciatus. (After Pat- "^^' maxillary palpus. 



ton and Cragg.). 

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

 rtim-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 



