MR. LUBBOCK ON THE THYSANURA. 597 



Length ^th. of an inch. 



Eound during winter and spring, under logs of wood. 



Some specimens, however, are paler and more reddish brown, wanting, apparently, 

 the dark green ; others are more green, from a deficiency of brown. 



Can this be the Podura viridis of Linngeus ? According to Bourlet, this is a variable 

 species, with somewhat the same range of colour as in my specimens, which, on the other 

 hand, were hairy and marked by a few spots ; whUe Bourlet says, " Peu de villosites," 

 and "sans tache." The I. pallida of Nicolet, which he considers as synonymous with 

 I. viridis, has the eyes much lighter. 



The body is about two and a haK times as long as the antennae. The mandibles have 

 respectively four and five teeth. The maxillae are short and stout. 



The three feet are similar ; they have no tenent hair ; the large claw has an external 

 tooth, and two small ones on the inner edge. The small claw has a single tooth on 

 the outer margin. 



The saltatory appendage reaches forward as far as the ventral tube. 



IsOTOMA LiNEATA, n. s. (PL LIX. fig. 9.) Colour dirty green, with a dark band running 

 down the back, and a spot of the same colour on the head. Eyes situated on a 

 black patch. Under side of body somewhat paler; saltatory appendage nearly 

 white. First abdominal segment decidedly narrower than the two preceding seg- 

 ments. Basal segment of the antenna rather shorter than the other three, which 

 are nearly equal in length. Body covered with short hairs, and with one or two 

 longer ones towards the posterior extremity. 

 Length Yoth of an inch. 



Found throughout the year, under logs of wood in Kent. 



This is perhaps the /. Nicoletii of Gervais (Apteres, pi. 50. fig. 12). In that case the 

 figure given by the eminent French entomologist is a very bad one, since the legs and 

 antennae are much too long in proportion, and the body is represented as having ten 

 segments. This latter characteristic, however, must be a mistake. From I. riparia, 

 Nic, it differs not only in colour, but also in the presence of the long scattered hairs. 



The body is about two and a half times as long as the antennae, which also (PL LIX. 

 fig. 9) are rather stout in proportion. 



The mandibles have respectively four and five teeth. 



The maxillge seemed to me to have seven processes — an inner single one, and on the 

 outer side two rows, each consisting of three. The outer processes are the largest. 

 The tarsi of the three pairs of feet are similar. 



There is no tenent hair ; the outer claw (PL LIX. fig. 10) is unarmed on the inner side ; 

 the small claw has a peculiar notch, rather than tooth, on the upper side. The saltatory 

 appendage, when turned forwards, reaches to the ventral tube. 



I have also some specimens of another species of Isotoma, which in many respects 

 resembles the I. virescens of Nicolet. 



In colour it is much like Orchesella pilosa, haviag dark markings on a greenish-grey 

 ground, and black eye-patches. The legs are light grey, the antennae a shade darker. 



