Two New Shade-Tree Pests. 59 



• 

 " worms " (Fig. 24.), varying from 2 to 7 or 8 millimeters in length. When 



full grown, these larvae leave their mines and drop to the ground. An inch or 

 less below the surface of the soil they make a small, thin, brown, papery 

 cocoon to which particles of soil adhere. In this cocoon the insect trans- 

 forms through a tender, white pupa into the small, black four-winged sawfly 

 shown much enlarged in Fig. 28. In this adult form the insect's body and head 

 are shining black, and measure about 3 millimeters in length ; when the wings 

 are folded they extend about a millimeter beyond the tip of the abdomen. 

 When expanded, the front wings measure about 8 millimeters across. The 

 antennae and femora are black and the tibiae and tarsi are light brownish with 

 blackish tinge, especially on the hind legs. The wings are quite dusky, con- 

 siderably more so than those of the elm species herein described. These two 

 species are easily distinguished by the position of the radial cross-vein (com- 

 pare Figs. 27 and 28) as indicated in the table* for separating the species of this 

 genus of sawflies. The females are provided with a saw-like ovipositor, as 

 shown in Fig. 3, with which their eggs are laid in the leaves. 



* The following table for separating the species of the genus Kaliosysphinga is given 

 by Konow, the European expert in this group of insects (Wien. Ent. Zeitung, Vol. V, 

 p. 269, 1886): 



A. The radial cross-vein meets the second cubital cell just before the second cubital 

 cross-vein — i. ulmi Sundeval (= intermedia Thorns). 



AA. The radial cross-vein lies behind the second cubital cross-vein. 



B. Third antennal joint twice as long as the fourth which is distinctly shorter and 

 thinner than the second — 2. putnila Klg. 



BB. Third antennal joint only about a half longer than the fourth. 



C. Fourth antennal joint scarcely longer and a little thinner than the second, 

 the third a good half longer than the fourth; wings clear — 3. dohrnii Tischb. 

 CC. Fourth antennal joint plainly longer and thicker than the second, the 

 third scarcely a half longer than the fourth ; wings very dark 



— 4. melanopoda Cam. (= nigricans Thoms). 

 In a foot-note Konow says : " Dohrnii is very nearly related to melanopoda and only by 

 a close observation of the characters given can it be separated; moreover, it is always 

 somewhat smaller, hardly 3 mm. long while melanopoda is somewhat longer." 



But in his description of melanopoda and in his table for separating it from its allies 

 (Mon. of British Phyt. Hym., Vol. I, p. 292, 1882) Cameron states that the third anten- 

 nal joint is "more than double the length of the fourth " which would put it in B instead 

 of BB in Konow's table. Cameron mentions dohrnii only in a foot-note (1. c. p. 291) say- 

 ing that the description of it so far as it goes, agrees with either pumila or melanopoda. 



The sawflies I bred on European alder in 1891 were determined by Konow (in 1896) 

 as Kaliosysphinga dohrnii Tischheia (Stettin. Ent. Zeit., Vll., 1846, p. 80). What is pro- 

 bably the same insect has been recorded several times in American literature under the 

 names melanopoda Cameron (Can. Ent. XXIII, p. 252) and ■varipes St. Fargeau (Can. 

 Ent., XXV, 59 and 247; Fletcher's Rept. for 1892, p. 147). According to Dalla Torre's 

 Catalogue (1894) pp. 122 and 287, Lepeletier (Count of St. Fargeau) described two sawflies 

 as varipes, now placed in the genera Emphytus and Priophorus, One of these is considered 

 a variety of E. tibialis and the other an aberration of P. t-adi. As neither of these species 

 work on alder, it is at least very doubtful if Harrington was correct in designating the 

 species injuring alder in Canada as Fenusa varipes St. Fargeau {melanopoda Cameron). 



