94 ENTOMOLOGICAL SOCIETY 



TABLES OF GENERA. 



Fam. CEstridae. 

 The larvae of these flies are true bots. 



1. Proboscis geniculate, deeply sunken in a long, narrow, oral slit ; 



palpi wanting ; arista plumose on the upper side (sub-fam. 



CuterebrincE] 2 



Mouth parts wanting, or rudimentary and lying in a slight concavity, 

 the head below having a closed appearance ; palpi sometimes 

 present; arista naked (sub-fam. CEstrincs} 3 



2. Third antennal joint short, oval or elliptical ; front not strongly pro 



duced ; abdomen vaulted, oval ; tarsi broad and flat, bristly 



gen. Cuterebra 



Third antennal joint much elongate ; front strongly produced over 

 the face ; abdomen flat ; tarsi thin and delicate... gen. Dermatobia 



3. Face with a median furrow, with or without a longitudinal dividing 



ridge 4 



Face with a broad, shield-shaped surface 5 



4. Median furrow very narrow ; apical cell widely open, not narrowed in 



the border gen. Gastrophilus 



Median furrow wide ; apical cell distinctly narrowed, or closed 6 



5. Palpi wanting gen. Hypoderma 



Palpi small, spherical. sub-gen. GEdemagena 



6. Median furrow without a dividing ridge its whole length ; apical cell 



closed aud petiolate, no stump of a vein at the bend of the 



fourth longitudinal ; body almost naked gen. CEstrus 



A narrow median ridge dividing the median furrow longitudinally ; 

 apical cell narrowly open, a stump of a vein at the bend of the 

 fourth longitudinal ; proboscis somewhat developed, with 

 labellae and large palpi ; body pilose g eu - Cephenomyia 



The following table for the determination of the larvae is 

 transcribed from Brauer's Mon. CEstr., 1863. It includes all 

 the North American genera. 



Larvee in Third Stage. 



i. Larvae with two pairs of jaws: two curved upper jaws, the so-called 

 mouth -parts, and two straight, horny lower jaws between the 

 ^first ; body abruptly truncate behind, wider than in front ; stig 

 mata on the last segment in a cavity which opens outwardly 

 through a transverse fissure, concealed, in the form of three 



