on abdominal segments. Proximal portion of legs yellow, distal 

 portion black. The sexual and other characters asfaras observed 

 differ but slightly from those of tripunctata and bimaculata. 



Length, 9-13 mm.; width, 1.2-2.0 mm. Average length, 12 

 mm.; width, 1.9 mm. The small specimens are obviously stunted. 



"Habitat, Decatur, Illinois, where it breeds in twigs of the 

 American elm, Ulmus americana. Described from many speci- 

 mens reared by Mr. E. S. G. Titus and collected by himself and 

 Mr. Webster. 



"Type, No. 6981, U. S. National Museum. Kindly presented 

 by Dr. S. A. Forbes, Director of the Illinois State Laboratory of 

 Natural History. 



"This species has a somewhat strong resemblance, in dark 

 individuals, to 0. bimaculata, while the pale forms approach 0. 

 tripunctata. In reality it is nearer 0. texana in appearance, but 

 has longer antennae than any of these. 0. texana is quite distinct 

 in having the paler parts, thorax, and ventral surface red, epi- 

 pleurse black, proximal portion of the legs reddish, head less 

 hairy, and abdomen comparatively strongly punctate." 



At present it does not appear possible to separate the early 

 stages of this group of species. While there are obscure dif- 

 ferences, there do not appear to be the necessary positive ones. 



The Egg. (PI. I., Fig. 2.) 

 Length, 3 mm.;width, 0.6 mm.; slightly reniform,of a creamy 

 white color, without perceivable reticulations. 



The hurra. (PI. I., Fig. 3.) 



Length, 14 mm. Head much smaller than thoracic seg- 

 ments, body decreasing in width posteriorly with moderate uni- 

 formity to the eighth segment, which is considerably smaller, i lie 

 anal still more reduced; body light straw-color, the two posteri- 

 or segments lighter; head anteriorly dark brown, posteriorly the 

 color of the body, mandibles darker than anterior portion of 

 head. Cervical shield brownish yellow, anterior surface smooth 

 polished, terminating posteriorly in a slightly raised, transverse 

 ridge. The apical declivity is shagreened. more finely posteri- 



