I'oMON.V C'OI.LEOE JOCHN.M, OK EnTOMOLOOY 611 



SYRPHIDAE 



Always anionic tin- plant licr arr to In- fnimd uri-i-iiisli. flat, .sticky-lookinjf 

 "worms" wliicli arc decidt-dly pointed at ono end and wliic-li do not liavf a distinct 

 lu'ad, eyes or legs. Tlifsc so-cnlU-d "worms" arr tlic larvir or maggots of a two- 

 winged insect or Hy of the order Diptera and tlie family Syrphidae, wliieli are 

 commonly called Syrpliid or Flower-Flies. The larva- (Figure iOS A) vary from 

 the minutest first-liatelied maggot to nearly an inch in lengtii, according to the 

 species to which it belongs. They are usually light or dark green, hut some may 

 he brown, orange, very liglit or nearly black. Those feeding upon the citrus plant 

 lice and herein described are green with a longitudinal darker green or brownish 

 stripe on the dorsum. The mouth is situated at the small end and all of the food 

 is obtained by puncturing the body walls of the lice and then sucking out the 

 contents. This operation is easily observed in the field. The maggot firmly sup- 

 ports itself by the large posterior end, raises itself up and begins to blindly move its 

 mouth-end about in quest of food. If it touches a plant louse it immediately raises 

 it into the air and sucks it dry. This is very rapidly repeated, with very disastrous 

 results to the lice. Wlien the larva is full grown it seeks some sheltered spot in 

 which to pupate (transform into the adult fly). This it may do on the stems or 

 upon tlie surface of a leaf. The pupa stage is shown in Figure 20.i B and is a 

 long, roundish or oval, brown body, which shows no signs of life. F'rom this 

 emerges the adult fly, which removes one end of the pupa case to escape. The 

 adults under consideration are dark with transverse yellow bands across the 

 abdomen as shown in the accompanying cuts. They are very swift fliers and are 

 often mistaken for bees. They are common around flowers, feeding upon the nectar 

 and from this habit get th<' names "Flower or Honey Flies." On hot days they 

 are sometimes very numerous and are called ".Sweat F'lies" in the F'astern states. 

 They deposit their eggs singly ui)on leaves and twigs which are infested with 

 plant lice and these give rise to the green larva?. 



While these insects do mucli to prevent the s|)read of the plant lice, they are 

 in turn preyed upon by other insects. Ants, which foster and protect the i)laiit 

 lice, kill and carry off the larva- in large numbers and greatly reduce their 

 efficiency. Internal parasites also prey upon them. I have hatched a large one 

 from the pupa- of Syrphus aincricaiius Wied. Insect Life, V^ol III, p. 1.5,S, reports 

 the internal parasite Ilemilrle-t syrphicola Ashm. as being reared from Allograpia 

 ohliijua Say. 



There are three species here which are doing good work in kee])ing down the 

 Citrus Plant Lice: a very large species. Lasiophlhicits pyrasiri Linn., tlie common 

 .Syrphid. Syrphux atiifricaiiux Wied.. and the small species Allograpia ohliijua .Say. 

 The following brief descriptions of the adult forms have lieen |)repared: 



*Lasiophthicus pyrastri I. inn. 

 (Figure -203) 

 This is the largest of the tliree species named above and measures seven- 

 sixteenths of an inch long. The large compound eyes occupy most of the head 



•NOTE. I am indebted to Prof. C. F. Baker, of P..ni..iia r,,llrifr. f..r the iden- 

 tification of these species. 



