280 



gated here. In 1844 Th. Hartig had already stated that the "Ambrosia" of Schmid- 

 berger is nothing but a fungus which he called Monila Candida, and that this fungus 

 constitutes exclusively the food of the Xyleborus larva. Eichhoff, on the contrary,- 

 believes that the exuding sap, and not the fungus, is the food of the larva. If you 

 can prove that the "Ambrosia" consists of Mycelium and animal matter, Schniid- 

 berger's explanation would be partially confirmed. Can you not send us authentic 

 specimens of dispar in both sexes ? — [January 25, 1890.] 



Since the above was written Miss Ormerod has kindly sent us British specimens of 

 Xyleborus dispar, both males and females, and after a careful comparison with North 

 American specimens of X. pyri, the males of which we possess through the kindness of 

 Mr. Fletcher, we can only confirm the opinion expressed by other entomologists that 

 the two are specifically identical. In other words, Peck's "Pear Scolytus," described 

 in 1817, is an imported species, which was brought into this country (probably first 

 to Massachusetts) early in the present or late in the past century. Until quite re- 

 cently only the female beetle was kuown in this country,* but Dr. Lintner and Mr. 

 Fletcher finally succeeded in finding the male, which in shape of body and other im- 

 portant characters strikingly differs from the female. 



In Europe this beetle is known as one of the few really polyphagous Scolytids, since 

 it not only attacks all sorts of deciduous forest trees, but also most of the cultivated 

 fruit trees and even Conifers (see Eichhoff, Europ. Borkask., p. 269). In North 

 America it has hitherto been observed only in various fruit trees (apple, apricot, 

 plum, pear, according to Harris), but it doubtless also infests forest trees, for little 

 attention is paid by our Coleopterists to the life habits of Scolytids, and there is dif- 

 ficulty in finding in situ those species which feed within the trunk. 



It may now be considered a settled fact that in this and other Scolytids which 

 enter the solid wood of trees, the galleries with all their ramifications are the work 

 of the female parent-beetle, which deposits her eggs irregularly in these galleries. 

 The larvse are not lignivorous, but their food consists of the peculiar substance already 

 alluded to above. 



Insects from Iowa. 



I send you in the same mail with this a few insects which I can not determine from 

 the collections here. If you can, through the columns of Insect Life, give me their 

 names and any further information concerning them, I shall be greatly obliged. 



Nos. 1 and 2 were reared in considerable numbers from the plum curculio, Conotra- 

 chelus nenuphar, No. 1 being far more common. I have no specimens of Sigalpliuscur- 

 culionis Riley, but these seem to differ from the description of that species in the num- 

 ber of the joints of the antennas and in the position of the ocelli, at least. 



No. 3 is a parasite upon the plum gouger, Anthonomus scutellatus. In every case 

 where the work of this parasite has been noticed the larval gouger had prepared its 

 place of exit from the plum pit. Otherwise the parasite could probably never escape. 

 The specimen that I send was cut from a plum where it had eaten its way to the skin. 



No. 4 were reared in large numbers early in the spring from the cocoons of Orgyia 

 leucostigma. 



No. 4 a are secondary parasites reared from No. 4. 



No. 5 were reared from the galls of Rhodites radicum. 



No. 6. This parasite was quite common here this summer on Meromyza americana. 



No. 7. Several of these flies have appeared in my breeding cages where cut- worms 

 were being reared. 



No. 8. This Tachina fly has been reared this summer from cut-worms and from the 

 stalk-borer, Gortina nitela. 



* It is certainly strauge that Dr. Harris, who cut quite a number of the beetles from 

 their galleries, never found a male specimen ; at least he does not refer to any differ- 

 ences between the specimens found by him. 



