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Show 278 INSECTA. rounded emargm. atl. on m. th e external side; l·n the preceding subge-nus it is straight( 1 ). very analogous by the short To these succeed other subgenerabd en and by the antenna!, form of the body, the tri·a n gular ha otmhe seta is simple or W·i th-much shorter than the head, but w ere out very apparent hairs. 1 margin of the last external In some, as in Eristalis, the ex~e~na te The body is generally . . strongly umsmua . cell of the wwgs IS 1 1 approximated at base. h a.u y. The antennre are c ose y M ALLO TA ' Meig '- Eristalis, Fab. · · t of the antennoo......, r1 'o rms a species of tra• nsversal Whe. re theh ela wsti JdOeisnt si. de o f h' 1 . s before and presentmg when w lC 1 I ' trapezmm,l tl' t' cal facet bordered all round(2). dilated an e 1P I HELOPHILus, Meig.-Eristalis, Meig. Fab. Where the palette of the antennre forms a semi·O va1 . The body is . h . the preceding subgenera. generally less hauy t an m 1 ·vre is terminated by a long tail, The body of several of t~e ~~ vers a queue de rat, or rat-tailed whence their vulgar appellatlo~ o 't erpendicularly to the surface worms. They elongate a~d rai~:: t~e live, in order to respire of the water, or cloa~re. m wh 't y They are f~rnished inter-h tl e aperture m Its extrem1 Y· . h throug 1 1 b 'Iliant trachere, whic 'near nally with two large and extreme y r~exus that are constantly in the origin of the tail, form numerous p motion. . f rain water contain numbers of these larvre. Their Reservoirs o • See Reaum., Ins., tal. l may eas'i1 Y be mistaken for filaments of roots. IV, xxx. L . H abeilliforme Reaum., Ins., IV, H. tenax; Musca tenax, ., . ' B and at 7 About the size of the male of the common e.e' b xx, • . . 1 The body IS rown, the first glance resembles It m co o~rs. . black streak covered with fine, yellowish-grey hairs, With a h side of on the front; two to four fulvous-yellow spots on eac the abdomen. (1) The E. intricarit~s, similis, alpinua, Meig. (2) See Meigen. DIPTERA. 279 The larva inhabits muddy water, privies and gutters, and is one of those called vera a queue de rat. It is said to be so tenacious of life that no pressure can destroy it( 1 ). Other Syrphidce differ from the last in the exterior and closed cell of the posterior margin; its external side being straight or but slightly sinuous. The antennce are elevated at base and advance almost parallel with each other; their last joint is almost ovoid or nearly orbicular. The anterior projection of the head is very short. 'fhe abdomen is generally narrower and more elongated than in the preceding subgenera. The wings, in those where it is shortest, are generally distant. SYRPHus, Lat. l\1Ieig.-8creva, Fab . Or Syrphus properly so called, where the abdomen is gradually narrowed from base to point. The larvre feed exclusively on Aphides of all kinds, frequently holding them in the air, and soon exhausting them by suction. Their body forms a sort of elongated cone, and is very uneven, or even spinous. When about to become pupce, they fix themselves to leaves, &c. with a kind of a glue. The body is shortened, and its anterior portion, which was previously the most slender, then becomes the thickest. 8. ribesii; Scceva ribesii, Fab.; De Geer, Insect., VI, vi, a. Somewhat smaller than the Musca vomitoria; head yellow ; thorax bronzed, with yellow hairs; scutellum of the same colour; four yellow bands on the abdomen, the first interrupted(2). ( 1) The Helophili of Meigen, and most of his Eristales, those in which the seta of the antenna: is simple, such as the aepulchralia, ameua, tenax, cryptarum, nemo-rum, arbuatorum, &c. . We might pass from the Helophili to the Calli cera:, Ceria:, Chrysotoxa, Paragi, Syrphi, terminate the division of those with n nasal prominence by the Bnccl1a:, and begin the division of those in which that elevation is wanting, with the Ascia: and Sphegina:, Insects closely allied to the Bacchre. Then would comeAphritis, Merodon, &c. This series would perhaps be more natural. (2) Lat., Ibid. See Meigen. The Chrysog(l3ter, Meig., appears to us to differ but slightly from Syrphus; the wings are incumbent on the body, a character whi~h also belongs to several species of the preceding subgenus. The antenna: are almost identical in both; but in Chrysogaster the front of the females is canaliculated on each side, the nasal eminence is lat·ger, and forms a small rounded lump, with an abrupt descent. . |
