416 



DIPTERA. 



t.(X-0 



barley, from six to ten larvoe being fennel in eacb, and by de- 

 stroying the flowers render tlie ear sterile. Oscinis frit Linn, 

 in Europe inhabits the husks of the barle}-, and destro^-s one- 

 tenth of the grain. Linnajus calculated the annual loss from 

 the attacks of this single species at half a million dollars. 

 Ploughing and harrowing are of no use in guarding against 

 these insects, as they do not transform in the earth ; the best 

 remedy lies in the rotation of crops. Man}^ of these small 

 flies, like the micro-lepidoptera, are leaf-miners, and are not 



readily distinguished from 

 them when in the larva state. 

 Of the genus Phora^ a 

 European species (P. incras- 

 sata Fig. 339 ; a, larva ; 6, 

 puparium) frequents bee 

 hives, and is thought b}- some 

 to produce the disease 

 which is known among apiarians as "foulbrood." 



In the pupiparous Diptera, namely, those flies which are born 

 as pupse from the body of the parent, the lar-\a state having 

 been passed within the oviduct, the thorax is more closelj'" 

 agglutinated than before ; the head is small and sunken in 

 the thorax, and in the wingless species this consolidation of 

 the head and thorax is so marked as to cause them to bear a 

 •remarkable resemblance to the spiders. Spider-like in their 

 looks, they are spider-like in their habits, as the names Spider- 

 flies, Bat-ticks and Bird-ticks, imply a likeness to the lower 

 spiders or ticks. The antennae are \evy deeply inserted and 

 partially obsolete ; the labrum is eusheathed hy the maxillae, 

 and the thoracic nervous ganglia are, as in the Arachuida, 

 concentrated into a single mass. 



HipPOBOsciD^ Westwood. The Forest-flies and Sheep 

 Ticks are characterized by the horny and flattened bod}', the 

 horizontal flattened head received into the front edge of the 

 thorax,, the large eyes, the rudimentary papilla-like antennae 

 placed very near together, and the proboscis is formed b}- the 

 labrum and maxillae, whose palpi are wanting ; the labium is 

 ver}' short ; wings with the veins present only on the costal 



