TENTHKEDINIDJE. 219 



albophaleratus, which usually makes a, mud cell situated in the 

 most diverse places, iu one case at least, makes no cell at all, 

 but uses the tunnel bored out by a Ceratina ! and yet we should 

 not split this species into two, on account of this difference 

 in its habits. We had written this before meeting with Mr. 

 Norton's remark that "it is difficult to give a hearty assent 

 to Mr. Walsh's inquilines or guest-flies, without further inves- 

 tigation." (Transactions of the American Entomological 

 So'ciety, vol. i, p. 194.) 



In Nematus the nine-jointed antennae have the third joint 

 longest. There is one costal and four subcostal cells, the 

 second cell receiving two recurrent veinlets ; the basal half 

 of the lanceolate cell is closed ; the hind wings have two mid- 

 dle cells, and the tibiae are simple. 



The larvse are hairy with warts behind the abdominal feet. 

 The}- have twenty feet, the fourth and eleventh segments (count- 

 ing the head as one) being footless. They are either solitary, 

 feeding upon the leaves of plants, or social and generally found 

 on pine trees, while some species live in the galls of plants. The 

 pupa, according to Hartig, is enclosed in an egg-shaped cocoon, 

 like that of Lophyrus, but less firm, though with more outside 

 silk. It is generally made in the earth, or in leaves which fall 

 to the ground. N. vertebratus Say is green, with the antennse 

 and dorsal spots blackish, the thorax being trilineate. There 

 are fifty species in this country, of, which the most injurious 

 one, the Gooseberry saw-fly, has been brought from Europe. 

 This is the JY". ventricosus King which was undoubtedly imported 

 into this country about the year 1860, spreading mostly from 

 Rochester, N. Y., where there are extensive nurseries. It does 

 more injury to the currant and gooseberry than any other native 

 insect, except the currant moth (Abraxas ribearia). Professor 

 Winchell, who has studied this insect in Ann Arbor, Michigan, 

 where it has been very destructive, observed the female on 

 the 16th of June, while depositing her cylindrical, whitish and 

 transparent eggs, in regular rows along the under side of 

 the veins of the leaves, at the rate of about one in forty-five 

 seconds. The embryo escapes from the egg in four days. 

 It feeds, moults and burrows into the ground within a period of 

 eight days. It remains thirteen da}-s in the ground, being 



