37° REPORT OF THE COMMISSIONERS OF 



August. Caterpillars of this insect are much more abundant in June than later, and 

 those observed in August and September must be considered representatives of a 

 second brood. There is possibly a third generation some years. The relative 

 scarcity of the caterpillars later in the season may probably be explained by the 

 increasing abundance of their natural enemies and it is by no means impossible that 

 some butterflies of the first brood may hibernate over winter as suggested by Pro- 

 fessor Weed. 



Common names. This butterfly has received a number of common names. One 

 widely adopted and perhaps best known in this country is the Mourning Cloak, a 

 translation of the German Trauermantel. It has also passed under the names of 

 Antiopa Butterfly and Willow Butterfly to a considerable extent, and the English 

 designations of Camberwell Beauty and Grand Surprise are worthy of mention. The 

 injurious caterpillar could easily be designated as the larva of the Mourning Cloak 

 or whatever common name is preferred, but it is simpler for a person interested only 

 in the practical side of the subject to use a special name for the caterpillar and 

 therefore, following Dr C. M. Weed, I have employed the designation of Spiny Elm 

 Caterpillar for this destructive larva. 



Food plants. This insect is more frequently brought to notice on account of its 

 depredations on the white or American elm, though it is also very injurious to wil- 

 lows and poplars but the small value of the latter two renders the damage of less 

 importance. The caterpillars are also recorded as feeding on the Hackberry, Celtis 

 occidentalis, and the butterfly has been observed to deposit its eggs on white and 

 canoe birch. 



Distribution. Mr Scudder in his work, TJie Butterflies of Neiu England, states 

 that this insect " is apparently distributed over the entire breadth of the northern 

 hemisphere below the Arctic circle as far as the thirtieth parallel of latitude." He 

 further states that it is found in nearly equal abundance throughout New England 

 and flies to but does not breed on the highest summits of the White Mountains. 



Natural eneniies. There are several insects which prey on this species. A 

 minute, four winged fly known as Telenomus graptcE How. watches its opportunity 

 to oviposit in the eggs of this butterfly. Pteromalus fuscipes Prov. , was reared in 

 Albany last summer from this insect. Three other Chalcids, Pteromalus vanessce 

 How., Pteromalus puparum Linn, and Entedon antiopce Pack., all minute, four winged 

 flies, attack the caterpillars, the former two sometimes in large numbers. Several 

 ichneumon flies are parasitic on this species in Europe but no records of such rearings 

 in America have been found. A dipterous parasite, Euphorocera claripennis Macq., 

 has been reared in this country from the caterpillars. A fierce ground beetle, 



