308 INSECTS AT HOME. 



(Scrophularia), from which the insect derives its specific name. 

 It has twenty-two feet, and varies much in colour after its 

 changes of skin. When it is full-fed, it leaves the i)lant on 

 which it has fed, and burrows beneath the soil at its root, 

 makin<]!^ for itself a cell below the surface of the earth, but not 

 spinning; a genuine cocoon. 



On Woodcut XXIX. Fig. 2, is a rather remarkable Saw-fly, 

 called Croesus se'ptentrionalis. In this genus the antennae are 

 composed of nine elongated and slender joints, as may be 

 seen at Fig. e. The wings have one marginal and four sub- 

 marginal cells, and into the second run two small nervures, 

 called ' recurrent ' nervures. The hind legs are large, and the 

 lirst joint of the tarsi very large and flattened. There are 

 many species of this genus, and the present species is a very 

 pretty one. The head, thorax, and base of the abdomen are 

 black and shining, and the rest of the body is bright red. 

 The legs are black, diversified with many white patches, as 

 seen in the illustration. The name Croesus is given to the 

 insect in allusion to the golden red of the abdomen. 



This is a very local insect, and though not generally spread 

 throiighout the country, is tolerably plentiful in places where 

 it does exist. Mr. F. Smith tells me that he has taken it near 

 Poole, feeding upon the alders that grew upon marshy ground. 

 iMr. Doubleday has taken it in Epping P"'orest, feeding on the 

 filbert. Tlie larvas are partly gregarious, dull green in colour, 

 spotted with black, and changing to yellow at the end of the 

 body. When they are alarmed, they protrude from between 

 the fore-legs a number of blackish tubercles, and withdraw 

 them when the danger has passed away. Like the larvoe of 

 the Cimbex, they roll themselves up if touched. When full-fed, 

 the grub seeks the ground, and constructs under the surface 

 a small cocoon, brown in colour, and very slight in texture. 

 Darenth Wood is mentioned as one of the localities in which 

 it is to be found. The larva of this species is shown at Fig. a. 



The fine insect shown on Woodcut XXX. Fig. 2, belongs to 

 the typical genus of this family, and is known as Tenthredo 

 zovatus. This genus has the antennas long and slender, the 

 third joint not being longer than the fourth. The wings have 



