VI 



. I N TEXXA TA THE ENTERIC CA XA L 



463 



30), Ephemeridae (ca. 40), Odonata (50-60), Plecoptcra (40-50), Orthoptcra (30-50 or 

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

 other hand few (i.e. 2-8) are found in the Corrodcntia (4-6), Thysann/it, ,-n (4), 

 lUiimchota (2-4), Neuroptcra (4-6), Panorpata (6), Trichoptera (6), Lepidoptera (6, 

 seldom 2 or 4), Diptcra (4 or 5), SipTionaptera (4), and Coleoptera (4-6). Tln-y 

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

 into a common duct, 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 Aphides there are on each side 



s( 



FIG. 321. Larva (maggot) of honey bee. anatomy 

 of the digestive and nervous systems (after R. 

 Leuckart). y, Brain ; bm, ventral chord ; oe, oeso- 

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

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

 gut ; vm, Malpighian vessels ; an, anus ; st, stigmata. 



oe 



FIG. 3-22. Enteric canal of 

 Psyllopsis fraxinicola (after 

 Witlaczil). oe, (Esophagus ; mrf, 

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

 pighian vessels ;'s, the coil formed 

 by the hind-gut and the must 

 anterior part of the mid-gut. 



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

 (Lepidoptera}, there are on each side 3 vessels with short common terminal pieces 

 (Fig. 348, p. 488). In Gallcria (Lepido2)tera) there is an unpaired terminal piece into 

 which 5 or 6 branched vessels enter. In Ephippigcra and the GryUidcc (Orthoptera} 

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

 a long common ductus excretorius. In Orthezia (Coccidcc) there are on each side 2 

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

 piece. The pupa; of the Jfoctuina have 3 pairs of vessels, united in pairs, entering an 

 unpaired urinary bladder. Lygaeus (Hcmiptera] has on each side 2 vessels entering a 

 urinary bladder. 



