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TEXT-BOOK OF ENTOMOLOGY 



(2) while to the chylific stomach a single pair of coecal appendages 

 (Orthoptera and larval Diptera, e.g. Sciara), or many caeca may be 

 appended; (3) the urinary tubes, also the rectal glands and the 

 paired anal glands. In a Hemipter (Pyrrhocoris apterus) appendages 

 arise from the intestine in front of the origin of the urinary tubes. 

 In certain insects a single coecal appendage (Nepa, Dyticus, Silpha, 

 Necrophorus, and the Lepidoptera) arises from the proctodseum. 



In certain larval insects, 

 as those of -the Proctotrypid;c 

 (first larval stage), the higher 

 Hymenoptera (ichneumons, 

 ants, wasps, and bees, Fig. 

 301), in the Campodea-like 

 larvae of the Meloidae and 

 Stylopidse, the larva of the 

 ant-lion (Myrmecoleo), and 

 those of Diptera impipara 

 (Melophagus), the embryonic 

 condition of the separation of 

 the proctodaeum and mid-gut 

 (niesenteron) persists, the 

 stomach ending in a blind 

 sac ; in such cases the intes- 

 tine, together with the uri- 

 nary tubes, is entirely secre- 

 tory. 



The anus is wanting in 

 the larva of the ant-lion, as 

 also in the wasps (in which 

 there is a rudimentary colon) 

 and in freshly hatched bees, 

 though it becomes perfectly 

 formed in the fully grown larvae (Newport, art. Insecta, p. 967, and 

 H. Midler). 



In the larvae of lamellicorn Coleoptera (Melolontha rulij<irix) the 

 digestive tube is nearly as simple as in bees, though there is a large 

 colon, which at its beginning forms an immense ccecum, and has also 

 one anal aperture (Newport). 



The length and shape of the digestive canal is dependent on the 

 nature of the food and also on the mode of life, especially the ease 

 or difficulty with which the food is digested. 



-el 



on 



FIG. 301. Larva of honey-bee : g, brain ; bm, ven- 

 tral nervous cord ; <, oesophagus ; *d, spinning-gland ; 

 cd, mid-intestine or chyle-stomach ; ed, hind-intestine, 

 not yet connected with the mid-intestine ; vrn, urinary 

 tube ; an, anus ; st, stigmata. After Leuckart, from 

 Lang. 



