128 



HARDWICKE'S SCIENCE-GOSSIP. 



and shortly pubescent. Many species are common ; 

 they occur chiefly on hedges and in grass, on the 

 stems oi reeds, and plants of low growth. The 

 abdomen at the tip curls inwards in the majority of 

 the species. 



Psilopiis, a genus of delicate, long-legged flies ; 

 congregates in small groups in shady spots. 



Dolichopus, Latr., found in marshy ground and 

 long grass, in rank herbage and about overgrown 

 pools ; a few species occur on the sea-coast. Degeer 

 has observed the transformations of D. tingulatus. 



Dolichopus trivialis, Hal. , metallic green ; face 

 above antenna; green, below whitish ; antenna; black ; 

 wings pale grey ; legs livid or pale yellow ; tarsi 

 black ; tibise spiny ; common ; variable ; long 4-5 mm. 

 Poecilobothrus ttobilitatus, L., brilliant metallic 

 green ; under-side of thorax with silvery-grey reflec- 

 tions ; face silvery below, green above ; antennae, 

 which are black ; legs pale yellow ; tips of posterior 

 tibiis, and all tarsi black ; wings clear ; a large 

 brown streak near the tip extending from fore to 

 hind border ; not uncommon ; long 5 mm. 



Diaphoris, Mg., and Chry solus, Mg., very small 

 and uncommon flies, metallic in colour, occurring 

 on trees in the hot sunshine. 



Argyra, Mcq., conspicuous by the whitish pu- 

 bescence on the abdomen in some of the species ; 

 generally distributed. 



Argyra diaphaiia, F., thorax blackish ; dorsum me- 

 tallic green ; abdomen greenish-black ; sides of first 

 two or three segments pale yellow, and from the 

 second segment to the tip, with whitish tomentum ; 

 face and antennae black ; wings pale grey ; legs 

 blackish-brown, tibia; lighter ; not uncommon ; 

 variable. The ground colour and markings of the 

 abdomen resemble those of Homalomyia caniculala ; 

 long 6 mm. 



Porphyrops, Mg., about twelve species — some not 

 uncommon. 



Hydrophonisy Whig. This, with Medeterus of 

 Fisch, are carnivorous genera (Doubleday and 

 Macquart both record having watched them devour 

 small insects.) The former inhabits the surface of 

 pools ; the latter frequents dry, warm localities, and 

 is conspicuous by its bulky proboscis. 



Thinophilus, Whlbg., three species ; rare ; sea- 

 coast. 



Sccllus notatus, F., metallic bronze ; sides of thorax 

 with whitish reflections ; face brown or black ; 

 whitish below antenna; ; antennje black ; wings with 

 brown streaks along the veins, and a distinct brown 

 spot on fourth longitudinal vein near the tip ; legs 

 blackish ; a few scattered spines ; not rare ; long 

 5J-6 mm. 



Campsicnemus, Wlk., found in damp grass, occur- 

 ing during the greater part of the year. C. scambiis 

 is not rare. 



The following plates aregood -.--Argyra leucocephala, 

 Wlk. i. PI. vii. 4. Mcdelerus diadema, Wlk. i. PI. vii. 



8. Psilopus Weidemanii, Wlk., i. PI. vi. I. Cam- 

 psiciicnms scambus, Wlk., i. PL vi. 6. Porphyrops 

 clcganUdus, Curt., 541. Scelhis notatus {Hydrophorus), 

 Curt., 162. 



23. Lonchopleridce, 



A limited group of small active flies, inhabiting 

 grassy marshes and such like habitats, being found 

 during the greater part of the warm weather. About 

 half a dozen species are British, two being tolerably 

 common, L. hitea, Pz., the commonest, being 

 yellowish-brown with black antennae and eyes, a 

 black spot on the vertex of the head and the centre 

 of the front of the pronotum ; a brownish-black 

 vertical stripe on the abdomen (variable) ; a thin 

 central brown line on the thorax, and dark tarsi. 



Lonchoptera hitea, Pz., Wlk., vol. i. PI. viii. I. 



24. Platypczidce. 



All the four European genera of this family are 

 British, representing about a dozen species, all more 

 or less uncommon, inhabiting woods, the larvae 

 living in fungi. 



Van Roser has published his observations on 

 P. boletina. Fall., the larva of which lives in rotten 

 mushrooms, and resembles a seed. Westwood 

 figures it in his " Class. Ins.," vol. ii. Fig. 130-17. 

 Walker illustrates /'.//Wfl', Mg., " Br. Dip." i. PI. viii. 

 I, and Callomyia elegans, Mg., PI. viii. 3. 



Curtis gives a good plate of Opetia lonchopteroides. 

 Curt., in his "Br. Ent." 489 ; mostly shining black 

 flies, about 4-5 mm. long. 



The genera may be recognised as follows : — 



Discal cell present. 



Fourth longitudinal vein simple : Callomyia, Mg. 



Fourth longitudinal vein forked : Platypeza, Mg. 

 No discal cell. 



Fourth longitudinal vein simple : Platyctiema, Lett. 



Fourth longitudinal vein forked : Opetia, Mg. 



Platypeza picta, Wlk. i. PI. viii. I. Opetia 

 lonchopteroides, Curt. 4S9. 



25. PipunculidiJ:. 



Allied to both the Plalypczida: and SyrphidiC (to 

 the latter, through the sub-family Bacchincc), Three 

 genera are European, two being British. They 

 inhabit fields and woods, and are in the habit of 

 hovering in the air ; they are not difficult of deter- 

 mination, but none can be said to be common. They 

 are larger than the Platypezidu:, and more stoutly 

 built. 



Discoidal cell present : Pipunculus, Latr. 

 Discoidal cell absent : Clialarus, Wlk. 



Pipunculus pratoriim. Fall., Curt. 757. Chalarus 

 spuriits. Fall., " Br. Dip." i. PI. viii. 7. 



26. Syrphida:. 



This extensive and well-known group is divided 

 into several sub-families, and represented in Britain by 

 over 200 species (about iioo species are European). 



As a rule the species of this family are flat-bodied. 



