3j4f NATURAL ARRANGEMENT OF INSECTS. 



black markings,, especially in the type Anthrax itself) 

 and which is likewise distinguished for its reniform 

 eggs, a structure rarely occurring among the Diptera. 

 As an elegant contrast to their deep mourning garb, 

 they are frequently decorated with bands of bright 

 silvery hair, which gives them an extremely beautiful 

 appearance. They are chiefly inhabitants of the warmer 

 climates, where they appear to abound. 



(835.) The third family of the TETRACH^T^, and 

 the sixth of the entire order, is occupied by the Brachy- 

 stoma. These have a short and membranous proboscis, 

 the terminal lobes of which are considerably thickened : 

 the third joint of their antennae is simple, with its seta 

 usually dorsal. They consist of insects of great variety 

 of form, and are separated into four tribes ; 1 . The 

 Xylotomidce ; 2. Leptidce ; 3. Dolichopido} ; and, 4. Syr- 

 phidce. The three first are distinguished by their lengthy 

 and slender legs, and frequently gay metallic colouring. 

 The majority are floral insects. In the Leptidce, we 

 find the remarkable genus Vermileo, the larva of which 

 forms a pitfall for its prey, very similar to that we have 

 described in giving the habits of the Myrmecoleon 

 among the Neuroptera ; and among the Dolychopidce, 

 the male legs of Medeterus are curiously distorted. The 

 last tribe of this family we find occupied by the Syr- 

 phidce, which certainly exhibit the most elegant insects 

 throughout the Diptera. They are usually depressed 

 and ornamented with beautiful colours. It forms a 

 very large group, embracing more than forty genera ; 

 and in which, consequently, the typical organisation 

 undergoes considerable variety of modification. In 

 Ceria and Callicera, the antennae are much developed, 

 and very elegant : in Volucella we find a mimicking 

 resemblance of the bee ; and which, also, in the larva 

 state, inhabit their nests : the Helophili are gay in- 

 sects, residing in the vicinity of water, especially where 

 there is an abundance of reeds and rushes : Merodon, 

 Tropidia, and Xylota have greatly enlarged posterior 

 thighs : Rhingia has an elongated clypeus and pro- 



