A HISTORY OF ESSEX individuals and prey upon many different kinds of larvae they destroy prodigious numbers, in some cases only leaving a few survivors out of large broods. The common House-flies (Musca corvina and M. domestica), the Flesh-fly (Sarcophaga carnaria), the blue and green Bottle-flies (Calli- pbora and Lucilia) also belong to this group, which includes many less familiar and more handsome species, such as the brilliant blue Cynomyia mortuorum, occasionally found in some numbers on the coast and less frequently inland ; the large glossy black Mesembrina meridiana, the wings of which have the basal portion conspicuously yellow, and Micropalpus pudicus. This, though by no means rare in the Colchester district, does not seem to have been identified from any other locality at present. The Horse Bot-fly (Gastrophilus egui), the Ox Warble-fly (Hypoderma bovis) and the Sheep Nostril-fly (CEstrus ovis) are also now classed with the Muscidee, but the literature devoted to them is already so voluminous and so easily accessible that it need not be added to here. The Antbomyidce and the families which follow them include many insects which perform an important part in the economy of nature by the removal of putrefying animal and vegetable substances ; also some that are very destructive to our crops, such as Pegomyia beta, which probably generally feeds on the wild beet (Beta marltlma) on the sea coast, but is occasionally very destructive to mangel-wurzel ; the Celery-fly (Acidia heraclei), the Carrot-fly (Psi/a rosci), and a number of beautiful little insects with spotted wings, among which the rare Gonyglossum wiedemanni and Icterica westermanni are especially noteworthy. When no other locality is mentioned in the list the Colchester dis- trict is to be understood. A LIST OF THE DIPTERA OCCURRING IN THE COUNTY CECIDOMYID.S (continued) Cecidomyia trifolii, F. Lw. Maldon (Fitch) ulmariae, Bremi. Maldon, Rayleigh (Fitch) urticae, Ferris. Essex (Fitch) veronicas, Vallot. Loughton (Fitch) Diplosis, Lw. botularia, Winn. Birdbrook, Maldon (Fitch) buxi, Laboulb. Birdbrook (Fitch) loti, Deg. Epping, Maldon (Fitch) Hormomyia, Lw. capreae, Winn. Maldon (Fitch) corni, Gir. Heltons Bumpstead (Fitch) fagi, Hartig. South Benfleet (Fitch) millefolii, Lw. Maldon (Fitch) piligera, Lw. Danbury, Epping NEMATOCERA PULICID.S Pulex, L. irritans, L. CECIDOMYIDA: Lasioptera, Mg. rubi, Schrk. Asphondylia, Lw. pimpinellse, F. Lw. Maldon (Fitch) sarothamni, Lw. Epping (Fitch) Cecidomyia, Mg. - bursaria, Bremi. Birdbrook (Fitch) - ? clausilia, Meade. Maldon (Fitch) - crataegi, Winn. Essex (Fitch) galii, Lw. Birdbrook, Maldon (Fitch) persicarias, L. Burnham (Fitch) plicatrix, Lw. "| - ? pruni, Kltb. I Maldon (Fitch) ranunculi, Bremi. J rosaria, Lw. Essex (Fitch) rosarum, Hardy. Maldon (Fitch) salicis, Schrk. Essex (Fitch) sisymbrii, Schrk. Romford (Fitch) taxi, Inch. Greenstead (Fitch) (Fitch) MYCETOPHILID^: Sciara, Mg. thomas, L. tilicola, Lw. Maldon (Fitch) Platyura, Mg. marginata, Mg. 1 80
