3. CHRYSOPS 423 



part of the mesopleurae and on the pteropleurse and metapleuras ; but there is no 

 trace of bristles or long bristly hairs anywhere on the thorax or scutellum. 



Abdomen moderately long, scarcely broader than the thorax but slightly narrowed 

 behind, composed of seven segments which are easily detected on the belly of the 

 female ; second segment longest, and the following ones gradually diminishing in 

 length ; basal part of the abdomen usually bearing conspicuous orange markings which 

 are very different in the two sexes. Genitalia in both sexes small and inconspicuous. 



Legs with two rather unequal spurs on each of the posterior tibiae ; front cox;b 

 considerably lengthened, about two-thirds the length of the femora ; femora 

 slightly shorter than the tibise. Pubescence fairly abundant on the anterior femora 

 and (in our British species) on the hind tibise; hind tibise rather thickened. 

 Pulvilli three, very distinct. 



Wings with conspicuous blackish markings, which usually form irregular bands 

 across thewings, and which are more extended in the male than in the female ; in 

 life the wings are extended half open when at rest. Venation quite in accordance 

 with the usual type of Tahanidce (figs. 239, 240) ; the four posterior cells always wide 

 open, and not even contracted at the tip ; anal cell normally closed at the wing- 

 margin, but sometimes slightly open. Squamae rather large, but with very slight 

 fringes except near the angle on the alar pair. Halteres with the knob rather large 

 and almost globular. 



Metamorphoses only recently observed, but Beling (Verh. zool.-bot. Wien, 

 xxxviii., ], 1888) found the larva and pupa of C. ca=cittiens in the mud thrown out at 

 the side of a swiftly flowing meadow-brook, while Hart and Hine have noted the egg- 

 laying habits of some American species. The perfect insects occur in the neighbor- 

 hood of water or wet places, and the females annoy cattle and human beings by 

 their persistent attacks. 



This genus is composed of a large number of exceedingly closely allied 

 species which occur in the Palsearctic region and in North America, and 

 it is known to extend all through Africa to the Cape of Good Hope, 

 in Asia through India and Java on to Borneo, in Central and South 

 America, and in Tasmania, but the genus is not yet recorded from New 

 Zealand nor with certainty from Australia. 146 species are enumerated 

 in Kertesz's Catalogue of the described species of the whole world 

 published in 1900. About twenty species occur in Europe and 

 about eight more in the Palsearctic region outside of Europe, while about 

 sixty have been described from North America ; at present we know four 

 British species, but two of these have been only recently identified, while 

 at least two more are hkely to occur. 



It is strange that almost all authors have considered Ch7'ysops 

 masculine but Chlorops feminine. 



Tabic of Species. 

 1 (6) Abdomen with at least some orange markings, even if only at the 

 basal corners. Wings with the outer margin of the middle 



— -e4«*es. 



Fig. 239.— Chry sops cwcutiens ? . x 6. 



dark band somewhat convex (fig. 239). Eace with shining 

 black calli which are separated by pollinose yellow spaces. 



