BIOLOGY AND STRUCTURE OF HYDROPHILUS CARABOIDES 655 



DESCRIPTION OF PLATE 27. 



Fig. 1. — Transverse section through rectal sac of mature larva of 

 Hydro phil us caraboidesat the anterior end ; high (ep) and low (epj)) 

 epithelial walls are visible. In the cavity of the sac are bits of torn and 

 ground chitin (c/i), swallowed together with liquid parts of food. 

 Duboscq, iron haematoxylin. Zeiss, ob. AA, oc. 2. 



Fig. 2. — Same, but in a larva of the first stage. Duboscq, iron haema- 

 toxylin. Zeiss, ob. AA, oc. 2. 



Fig. 3. — Part of longitudinal section of middle intestine (stomach) with 

 crypts (crp) of a larva of first stage, mt, circular muscles ; ml, longitudinal 

 muscles. Duboscq, Giemsa's stain. Zeiss, ob. '/,„ hom. imm., oc. 1. 



Fig. 4. — Crypt of stomach of mature larva. Duboscq, iron haema- 

 toxylin. Zeiss, ob. Y,., hom. imm., oc. 1. 



Fig. 5. — Oblique section of Malpighian tubule of mature larva. In the 

 protoplasm of cells conspicuous differentiation of layers and copious 

 accumulation of pigment grams (pg). Duboscq, Unna's Polychr.- 

 Methylenblau. Zeiss, ob. ^/,2 hom. imm., oc. 0. 



Fig. 6. — Same, in a larva of first stage. Duboscq, iron haematoxylin. 

 Zeiss, ob. Vjo hom. imm., oc. 0. 



Fig. 7. — Hair {chf) of chaetoid ty])e from back of larva. Under the hair 

 is the usual hypodermic cell (hp). ch, chitine. Duboscq, iron haema- 

 toxylin. Zeiss, ob. Yi> hom. imm., oc. 2. 



Fig. 8. — Hair with thaeca (tc) and ampulla {etc) consisting of two — the 

 thaecogenous and trichogenous — cells, ch, chitin ; hp, hypodermic cell ; 

 cA^ chaetoid. Duboscq, Giemsa's stain. Zeiss, ob. 7]2 hom. imm..oc. 2. 



Fig. 9. — Hair (tr) with double thaeca {<c,, tCo) and attending nerve 

 (7is t 111) ; fc, ampulla ; hp, hypodermic cell ; chi, chaetoid. Duboscq, 

 iron haematoxylin. Zeiss, ob. Y,., hom. imm., oc. 4. 



Yy2 



