70 



HOW TO COLLECT 



" O^stridoi (Bot- and Gad-, or Warble -fiiefc>) 



are said to hover over mountain- tops. Ilypoderma, 



however, is generally to be taken sitting on 



bare sunny places, in roads, heaths, etc. Gas- 



trophilus is often to be seen round horses, and 



may sometimes be taken with a net ; but it may 



be noted that it is labour wasted to attempt to 



catch specimens of this genus with a ivhite net. 



Cephenoimyia sits on stones in spots frequented by deer, and is said 



to settle not infrequently on human beings who enter its haunts. 



'■^ Muscidm Acalypteratce are to be taken as a rule 



by sweeping, though a few Ortcdidce, Micropezidce, 



Trypetidce, etc., may be captured on leaves and flowers, 



as well as on carrion and ordure. 



GASTROPHILUS EQUI. 



TRYPKTA COBNUTA. 



" Other Families. — As regards other families, many of them will be 

 met with while seeking for those already mentioned ; and though the 

 habits, etc., of the remainder are as varied as in the case of the latter, 

 still the specimens encountered fortuitously will probably mount up 

 to a considerable number." 



Method of Collecting. 

 If possible, Diptera should always be brought home alive in the 

 glass- bottomed pill-boxes (to which they are to be transferred on 

 being captured in the net), and should then be killed in the cyanide- 

 bottle or jar immediately before being pinned. As soon as a fly is 

 taken in the net by a dexterous sweep, a sharp turn of the wrist 

 must be given (following a smart downward or lateral stroke in 

 order to bring the fly to the end of the net), in such a way that the 

 end of the net containing the insect falls over the rim and so makes 

 a closed bag from which it cannot escape. The end of the net can 

 then be gathered up in the hand, and the fly forced into a still 

 smaller space, in which it will not be difficult to get it into a pill-box, 

 and then to slip on the lid. If the specimens are small, it is possible 

 with care to get several into one pill-box. Flies may also be 

 transferred direct from the net to the killing-bottle, and so brought 

 home dead ; but this method is not to be recommended, since prolonged 

 exposure to the effects of cvanide of potassium is apt to injure the 



