VI 



ANTENXATA—THE ENTERIG CANAL 



463 



30), Ejyhemeridae (ca. 40), Odonata (50-60), Plecopiera (40-50), Orthoptera (30-60 or 

 more), and Symcnoptera (very numerous, often over 100, seldom below 12). On the 

 other hand few (i.e. 2-8) are found in the Oorrodentia (4-6), Thysanoptera (4), 

 Mhynchota (2-4), Neii^ro^itera (4-6), Panorpata (6), Trichoptera (6), Lepidoptera (6, 

 seldom 2 or 4), Diptera (4 or 6), Siplionaptcra (4), and Colcoptera (4-6). They 

 generally enter the hind-gut separately, but occasionally the vessels of each side unite 

 into a common duot, and sometimes the ducts from the two sides also have a common 

 unpaired terminal piece. Here and there the vessels open into a paired or unpaired 

 urinary bladder attached to the hind-gut. In the Apihides there are on eacli side 



Fig. 321.— Larva (maggot) of lioney bee, anatomy 

 of the digestive and nervous systems (after R. 

 Leuckart). g, Brain ; hm, ventral chord ; oe, ceso- 

 phagus ; sd, spinning glands ; cd, mid-gut, or chyle 

 stomach ; ed, hind-gut, not yet connected with the raid- 

 gut ; vm, Malpighian vessels ; a?i, anus ; st, stigmata. 



Fig. S22.— Enteric canal of 

 Psyllopsis fraxinicola (after 

 Witlaczil). oe, (Esophagus ; md, 

 mid-gut ; ed, hind-gut ; vm, Mal- 

 pighian vessels ;'s, the coil fonned 

 by the hind-gut and the most 

 anterior part of the mid-gut. 



2 vessels which unite together before entering a common duct. In Aletia, Danais 

 {Lepidoptera), there are on each side 3 vessels with short common terminal pieces 

 (Fig. 348, p. 488). In Galleria {Lepidoptera) there is an unpaired terminal piece into 

 which 5 or 6 branched vessels enter. In EpMppigera and the Gryllidce {Orthoptera) 

 there are numerous vessels which, uniting into a tuft, enter the hind-gut through 

 a long common ductus excretorius. In Ortliezia (Coecidce) there are on each side 2 

 vessels which unite. The 2 terminal ducts themselves enter an unpaired terminal 

 piece. The pupae of the Noctmim have 3 pairs of vessels, united in pairs, entering an 

 unpaired urinary bladder. Lygaeus {Hemiptera) has on each side 2 vessels entering a 

 urinary bladder. 



