Maskell. — On some Gall-i^roducing Insects. 255 



The following descriptions of these insects are offered : — 



Order. HYMENOPTEEA. 



Sub-order. Terebrantia. 



Family. Chalcididjs. 



Genus Eurjrtoma. 



Eurytoma oUarice (Gall-fly of Ake-piro). Plate XI., figs. 1-16. 



Insects inhabiting in the larval and pupal states, in colo- 

 nies, excrescences and abnormal growths (galls) (figs. 1,2) on 

 the twigs of Olearia fitrfuracea. The galls are probably not 

 produced by themselves, but by a dipterous insect. (See be- 

 low.) 



Larva (fig. 3) about yV^^- iii length, grub-like, fleshy, yel- 

 lowish ; no true legs, but a number of very obscure tubercles ; 

 the head (fig. 4) exhibits a convoluted ring with two conical 

 processes within it. On each joint of the body there are two 

 minute circular spiracles (fig. 4). 



Pupa (fig. 5) black, exhibiting the immature organs of the 

 imago. The pupa is enclosed in a hard, grey case (fig. 5a), 

 which has all the appearance of the dried larval skin. As 

 coarctate pupse are not, seemingly, found amongst the Hymen- 

 optera, this case must be taken as an exceedingly closely- 

 W'Oven hard cocoon. 



The perfect fly (fig. 6) is about j^in. long ; colour black, 

 covered with short, fine, grey hairs; antennae black; legs 

 yellow ; wings dark-grey. The head is transverse ; eyes 

 large ; palpi short ; thorax thick ; mesothorax large and some- 

 what elevated ; scutellum small. Abdomen (fig. 13) apparently 

 composed of three parts — a short peduncle, a median cylin- 

 drical portion, and an oval hinder region with six or seven 

 segments. The ovipositor of the female and the penis of the 

 male are not usually exserted. AntennaB of both sexes (fig. 7, 

 female ; fig. 8, male) with twelve joints, of which the first two 

 are very short, the third much the longest, the remaining 

 nine sulD-equal, each slightly dilated at the tip ; all the joints 

 except the two first hairy. The antennae of both sexes are 

 very similar : that of the female may be distinguished, perhaps, 

 by being proportionately shorter than that of the male, and 

 the joints after the third rounder. Feet (fig. 9) slender ; the 

 femur only moderately thick ; the tibia dilated at the tip and 

 bearing a spur ; tarsus of five joints. The spur of the tibia ou 

 the two front legs (fig. 10) is peculiarly large, apparently cleft 

 in the middle, with serrated edges ; and the first joint of the 

 tarsus has a distinct comb of stiff bristles on its inner side. 

 The spur on the tibiae of the other pairs of legs is a simple 

 spine (fig. 11), and the tarsus bears no comb. Fore- wings 

 (fig. 12) hairy, with very few veins ; the sub-costal and anal 



