FAMILY OESTRIDAE : CLASSIFICATION 315 



be found scattered all over the floor of the laboratory. These larvae will 

 even crawl out of a large glass jar. From experience it has been found 

 that the)- never leave the mud enclosure, but always pupate in the sand. 

 This enclosure has the further advantage of minimizing the smell from 

 the decaying meat ; if the latter is left in a tray or glass jar it becomes 

 unbearable. The enclosure will be referred to again in connection 

 with the breeding of Musca. 



FAMILY OESTRIDAE 



Medium to large flies with thick-set bodies, large heads and rudiment- 

 ary month parts. Antenna short, three-jointed and hidden from view in 

 the facial groove. Front wide in both sexes ; eyes comparatively small. 

 The thorax has a distinct transverse suture ; the squamae are as a rule 

 large, but may be small. Wing venation of the muscid type ; the first 

 posterior cell is either narrowly open or entirely closed. 



This family consists of a comparatively small group of flies of the ut- 

 most importance to the veterinarian, and of the greatest interest to the 

 dipterologist. They are popularly known as ' Bot flies ', ' Warble flies ', 

 or ' Breeze flies '. The mature insects are as a rule found either in the 

 open country resting on leaves, or on the ground along roads and path- 

 ways frequented by the hosts which they parasitize. 



The great economic importance of the Oestridae has long been recog- 

 nized, and it is not, therefore, surprising to find that their life histories 

 were known to Linnaeus and many of the older entomologists. The best 

 modern account of this family is that of Brauer, who unquestionably had 

 the most profound grasp of the subject ; his monograph is still the 

 standard work on the structure and life histories of the Oestridae. 



Numerous attempts have been made to classify the Oestridae, first ac- 

 cording to the structure of the 'larvae, and secondly according to their 



habits. They were formerly divided into two groups, 

 ....... , Classification of 



those in which the larvae have oral hooks, and those the Qestridae 



without external mouth parts. Brauer points out that 

 though this grouping is useful in distinguishing the full-grown larvae, it 

 is incorrect, as all oestrid larvae have oral hooks when very young. It is 

 also an unnatural classification, as no relationships exist between the two 

 types of full-grown larvae and the perfect insects. 



Clark suggested the second method of grouping the larvae, viz., to 

 arrange them according to their habits, into cavicolae, cuticolae and 

 gastricolae, but. Brauer. points out that this classification is also 



