ENTOMOLOGY IN OUTLINE — DIPTERA. 91 



Suborder CYCLORRHAPHA. 



The second suborder into which the Diptera are divided is tlie Cyclor- 

 rhapha. which inckides all those flies which make their escape from the 

 pupa case, or larval skin, by a round opening formed in the top by the 

 imago pushing out its head, the first suborder which we have been con- 

 sidering escaping through a slit made in the back. 



1. Syrphidse, the Syrphus-flies. 



2. Pipunculidse, the Big-eyed flies. 



3. Platypezidse, the Flat-footed flies. 



4. Phoridse, the Humpbacked flies. 



5. Conopidse, the Thick-head flies. 



6. ffistridee, the Botflies. 



7. Muscidse, the Muscids. 



8. Hippoboscida^, the Louse-flies. 



9. Nycteribiidse, the Bat-ticks. 

 10. Braulida?, the Bee-louse. 



The family first to be considered here is the Sypphidse, in which we 

 find several beneficial species. This is a very large family and includes 

 over 700 species so far named and described. They are moderate-sized 

 insects and are great mimics, many of them strongly resembling bees, 

 wasps, and other insects. In fact, the Eristalis tenax, or drone-fly, so 

 strongly resembles the honey-bee that it is frequently mistaken for it, 

 the principal difference being in the fact that it is a dipterous insect, 

 while the bee has four wings. Another difference is that this insect 

 has no sting, although its strong resemblance to the honey-bee admon- 

 ishes the ignorant to avoid it. The larva of this fly lives in cesspools 

 and decomposing filth of any kind. It is provided with a long breath- 

 ing tube, which is a continuation of the abdomen, and it is connnonly 

 known from this appendage as the "Rat-tailed larva." 



A common meiuber of this family is a black and yellow banded 

 insect, much resembling a yellowjacket, which- may be seen hovering 

 motionless in the air over flowers on a summer day, making a sudden 

 dart occasionally in one or another direction. The larva of this is pre- 

 daceous on aphids, and is one of the many beneficial insects to which 

 we owe so much. 



The larvae of the different species of Syrphus-flies have various feed- 

 ing habits; some, as stated above, are predaceous on aphids; some feed 

 on decaying animal and vegetable matter; some are found in the nests 

 of ants, and others in the nests of bumblebees and wasps. 



The Pipuneulidse, or big-eyed flies, are remarkable mainly for the 

 disproportionate size of their eyes, which seem to swell the head beyond 

 the size of the body. They frequent plants and are parasitic on bugs. 



