62 ENTOMOLOGY FOR MEDICAL OFFICERS 



i-Free edge of scutellum simply convex : palpi about as long as the 



2. \ proboscis in both sexes = Epiahirgi. 



Ipree edge of scutellum trilobed = 3- 



(•Metanotum bare = Cuhcales. 



3. \ Metanotum with a few bristles, or scales, or both 



\ = Metanototricha. 



Theobald has done great service by pointing out the 

 value, for purposes of classification, of the form and arrange- 

 ment of the scales. The following (Fig. 19) are the principal 

 kinds of scales — not including bristles, hairs, and "hair-like 

 scales " — recognised by this authority : — 



On the head: curved scales (Fig. e,f, k) which will here 

 be called " sickles " ; forked scales (Fig. a, b, c, d), which will 



g h k I m n 



Pig. 19.— Scales of CuUddle. 



here be called " darts " ; and flat scales (Fig. k, /, ;;/, n), which 

 will here be called " squames." All three kinds vary a good 

 deal in detail : all three may coexist (as in Culex) ; or 

 squames alone (as in Megarhinus), or darts alone (as in 

 certain species oi Anopheles) maybe present; or there may 

 be a combination of squames and darts (as in certain species 

 of Stegomyid). 



On the thorax, hair-like scales, "sickles" of different 

 forms, and " squames," which may be spatulate, or broadly 

 elliptical, or narrowly elliptical : both hair-like scales and 

 squames may be present (as in Stegomyid), or hair-like scales 

 and sickles (as in Culex), or elliptical squames alone (as in 

 Megarhinus), or (as in some species oi Anopheles) there may 

 be nothing but hairs. 



