Two New Shade-Tree Pests. 123 



not until May 27th, 1904. that I first saw the aduh insect which was then 

 present on the ehii leaves in large numbers. The pest is evidently the 

 common elm sawfly leaf-miner of Europe, Kaliosysphinga ulmi, Sun- 

 deval.* I have found the insect working on the European elms scattered 

 through the city of Ithaca, and it is apparently on the increase. It doubt- 

 less occurs in most localities in New York, and perhaps in other States, 

 where European elms are planted. The insect must have been in this 

 country at least ten or fifteen years. 



In England and Scotland, this elm pest is common but apparently 

 rarely does noticeable injury. It is also widely distributed through 

 Sweden, Germany, France, and Russia. 



The insect. — The adult insect (Fig. 27) is a small, shining-black 

 sawfly measuring about three millimeters in length, with its wings pro- 

 jecting beyond the body a little. The wings expand to about eight milli- 

 meters across. The antennas and femora are black and the remainder of 

 the legs are light brown with a blackish tinge. The wings are consider- 

 ably clearer than those of the alder sawfly (Figs. 27 and 28). The saw- 

 like ovipositor of the female is shown in Fig. 2y.] The eggs are stuck 

 into the elm leaves (Fig. 25), and the tiny whitish larv?s which hatch 

 therefrom begin life at once as miners, finally consuming practically all 

 of the interior tissues of the leaf over an area about half an inch in 

 diameter. Full-grown larvae measure about seven millimeters in length, 

 and several are shown in Fig. 24. I found no striking characters for 

 distinguishing them from their near relatives working in alder leaves. | 



* This species was described in 1847 by Sundeval (Forhandl. red de Skand. 

 Naturforsk. Christiana, pp. 240, 241). For other European references see Dalla 

 Torre's Catalogus Hymenopterorum, Vol. i, p. 158, and Cameron's Mon. British 

 Phyt. Hym., Vol. i, p. 295. This species is easily separated from the others in the 

 same genus by the position of the radial cross-vein as given in Konow's Table on 

 p. 59, and which can be readily seen by comparing the wing venation in Figs. 3 and 8. 



t It is an interesting fact that every specimen of over 125 of the sawflies collected 

 one day on elm leaves at Ithaca, N. Y., were females. Further collections gave 

 similar results ; I have seen no males during two seasons' observations. Cameron 

 says the males are " similar, but with thicker and longer antennae, the joints from 

 the fourth being perceptiljly thicker than the basal ones." Brischkc says (Beob. 

 Arten der Blatt und Holzwcspen, 1883, p. 261, as intermedia) in his brief account 

 that lie knew only the females. 



t The very young larvae are said (Healy in The Entomologist, for 1896, p. 298) 

 to liavc a large dark spot on the venter of the first thoracic segment, with two small 

 brown dots on each side and a small black dot on the venter of the remaining body 

 segments, except the last. But at the first moult these decorative markings are all 

 tlirown off. Tlie full-grown larva is distinctly segmented and of a wliitisli color 

 witli the green food particles giving it a greenish tinge. The much flattened head 

 is light lirown with mandibles darker. The six true legs are slightly brownish and 

 are little used, the larv?e moving about in their mines with a wiggling motion of 

 the whole body. Rudimentary pro-legs are present on segments 5 to 12. 



