1072 NOTES ON A NEW DIPTEROUS INSECT, 



and every part of the plant, from the root to the flower, is liable to 

 an attack from a distinct form of Cecidomyidce. The "Hessian- 

 fly " lays its eggs on the leaves of the wheat, and the larvse when 

 hatched make their way down the leaf and congregate within the 

 sheath. Although my acquaintance with the insect before our 

 notice dates only from an advanced stage of the larval state, I feel 

 convinced, from the appearance of the stem, that the eggs are 

 deposited in that situation in the first instance and not on the leaf 

 or spathe. The larvae are found concealed in the stalk under the 

 spathe (without any other indication of ingress than a microscopic 

 puncture which I presume to have been made by the female 

 ovipositor), where they form delicate white tilmy cocoons pre- 

 vious to assuming the pupa state. The larvae are of a bright 

 safi'ron or orange colour, and are in length about a line and a-half 

 when full grown. I exhibit specimens of these dried, and in spirit, 

 also the cocoons and pupje. I have also made enlarged sketches 

 of the insect in larva, pupa and imago states, in order that you 

 may be better enabled to distinguish their appearance, the speci- 

 mens themselves being so diminutive. I am unable to state the 

 length of time this insect remains in the larval state. These 

 particular individuals were for some time enclosed in a dark 

 box, but emerged a few days after having been transferred to 

 another case with a glass cover, and placed in the sun. From 

 what I have remarked with reference to the cocoon, it will of 

 course be inferred that the insect undergoes its metamorphoses 

 in the grass. Many larv^ of the Cecidomyidce, however (in- 

 cluding the genus Lasiojjtera)^ leave the food-plant ;ind conceal 

 themselves under ground to undergo their transformations. 



I refrain from now giving a desci'iption of this interesting insect, 

 which I propose to call Lasioptera vastatrix (in allusion to its 

 destructive character), as it will be included in a monograph 

 of the Australian Cecidoinyidte which I hope to read at our 

 next meeting. 



Two small species of Hymenopterous insects belonging to the 

 Proctotrujmkfi emerged with the specimens of L. vxstatrix, and 

 are evidently parasitic upon it. They appear to be species of 



