STATE HORTICULTURAL SOCIETY. Ill 



with her slender ovipositor and deposits an egg therein, and passes on to 

 another to repeat the operation. This egg produces a minute grub or 

 larva, which ultimately destroys the life of its victim, and comes forth a 

 fly, similar to its parent. 



The description of a few species will be sufticient to convey to the 

 reader an idea of these useful insects, which is all that is necessary for 

 present purposes. 



Aphidius Lactucaphis, Fitch. Lettuce-louse Aphidius. 



Deep black, legs trimmed with brownish ; antennae 19-jointed, sec- 

 ond joint smallest, globular, third joint longest with a slight constriction 

 in the middle; tvings slightly smoky, outer marginal vein and vein bor- 

 dering the cell beyond the stigma black, outer veins brown, stigma 

 white; abdomen long, obovate, flattened, rather narrower than the tho- 

 rax, tip rounded. Length, o 06 inch. 



The names given indicate the species of Aphis upon which these 

 insects are known to be parasitic ; but it is not probable they are con- 

 fined to a particular species. 



Aphidius i^Praon) polygonaphis, Fitch. The Knotweed-louse Aphidius. 



Black and shining ; abdomen slender and elliptical, of a bright sul- 

 phur-yellow color, tinged with dusky above and beneath the tip, with 

 broad yellowish bands at the anterior sutures, base narrowed to a short 

 pedicel, which, with the legs and base of the antennas, are reddish-yellow; 

 Antennae, 17-jointed. Length, 0.08 inch. 



Apcidius {Praon) viburnapliis, Fitch. Cranberry-louse Aphidius. 



Black and shining, similar to the preceding, but the abdominal ped- 

 icel and the legs only, yellowish; antenUcC, 15-jointed. 



Aphidius {Praon) avenaphis, Fitch. Grain-louse Aphidius. 



Black ; legs, base of the abdomen and also a sub-basal band, yellow; 

 abdomen as long as the thorax, but narrower, oval, first segment forming 

 a pedicel ; antennae as long as the body, slender, 20-jointed, black ; tho- 

 rax egg-shaped, black and shining. Length, o.io inch. Parasitic on the 

 oat or grain Aphis {Aphis avence). 



Toxares triticaphis, Fitch. Wheat-louse Aphidius. 



Black, shining; antennae threadlike, longer than the body and 25- 

 jointed ; thorax egg-shaped and rather broader than the head ; abdomen 

 flattened, long, oval, a little longer than the thorax, but scarcely as broad. 

 Wings transparent, slightly smoky, strongly iridescent; stigma pale 

 brown; veins brownish black. Length, 0.08 inch. Parasitic on Aphis 

 avena. 



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