106 FIFTH ANNUAL REPORT 



I have always found associated with this bark-borer another larger 

 borer, {Saperda disooidea Fabr.), an insect in which the two sexes 

 differ so remarkably, both in size and coloration, that the male was 

 subsequently described as fusoipes by Say, and whose larva, before 

 maturing, penetrates the solid wood. 



NATURAL ENEMIES. 



I have bred two interesting parasites from this Soolytus. They 

 both belong to the same subfamily {BraGonide8) of the Ichneumon- 

 flies as the two parasites of the Plum Ourculio, (od Rep., pp. 24-28), 

 and according to the eminent Hymenopterist, Mr. E. T. Cresson, to 

 whom I am under obligations for so many favors, they are both unde- 

 scribed. Their larvae, after killing the bark-borers, form little pale 

 cocoons in which to undergo their transformations. The first may be 

 called the Three-banded Spathius. The genus was characterized by 

 Esenbeck, who believed that the insects composing it deposited their 

 eggs in the larvee of leaf-eating beetles. 



SrATiiius TKiFASCiATUs, N. Sp. — $ . Average length, 0.18 inch. Color, light-brown, 

 jffcaf^ pubescent, palpi long and pale ; eyes black; ocelli black, contiguous; antennas 

 smooth, pale, and reaching to secoiad abdominal joint. Thorax with sutures dark- 

 brown ; legs more or less dusky, the tarsi (except at tip) an annulus at base of tibia3, and 

 the trochanters, pale ; wings fuliginous, with a white fascia at base, at tip and across 

 outer middle of front wing, including the inner half of stigma, the outer half of which 

 is dark-brown ; middle fixscia most clearly defined. Abdomen slightly pubescent at sides 

 and tip ; flrst joint pale, petiolate, and with short and longitudinal aciculations above ; 

 second joint pale above, tlie others more or less brown ; ovipositor pale, dusky at tip, 

 and as long as abdomen. 



One bred specimen. 



^ — Differs in being much darker colored, the head, thorax and femora being brown 

 and the metathorax and base of first abdominal joint black. 



One bred specimen. 



The second is a lly of about the same size, and belongs to the ge- 

 nus Braoon. Mr. Cresson has described it in MS., and I append his 

 description : 



Bracon scolytivorus, Cress. — 5 — Black, shining, metathorax and base of ab- 

 domen pubescent; face, anterior orbits, lower half of cheeks, clypeus, mandibles, 

 except tips, palpi, tegulfc, legs, including coxai, and abdomen, honey-yellow, the latter 

 dai'ker; posterior coxoa sometimes dusky; antenna? at base beneath, dull testaceous ; 

 wings fuliginous, apical half paler, iridescent ; abdomen shining, first segment whitish 

 laterally, the base and disc sometimes duskj'^; base of second segment with a large sub- 

 triangular flattened space inclosed by a deep groove, the posterior side of which is gen- 

 erally blackish ; ovipositor longer than abdomen ; sheaths black ; length, .15 — .17 inch. 



d" — More pubescent ; posterior coxre blackish, also the femora above, especially 

 the posterior pair ; posterior tibiaj dusky ; abdomen black, polished ; apex of first, basal 

 half of second and sides of apical segments more or less hone.y-yellow ; sides of basal 

 segment whitish ; wings paler; abdomen narrower and rather more convex; length, 

 .16 inch. 



Three d', three $ specimens. 



