848 WAHLGREN, ON SOME APTERYGOGBNEA. 



inner roio is tlie most posterior of all. The upjier clcno is pro- 

 vided with three teeth, the lower claio uyiarmed. The mucro is 

 provided with one tooth. 



The ground-colour is white. The markings are different on 

 difFerent specimens, but they are always distributed according to 

 a strict law. The most pigmented specimen has a black spöt 

 between the bases of the antennse, black eye-spots, a black cross- 

 bar along the front margin of the second thoracic segment and 

 four black spöts so near together that they almost form a cross- 

 bar on the third thoracic segment; on the first abdominal seg- 

 ment spöts are always wanting; on the second abdominal seg- 

 ment there are four spöts almost forming a cross-bar, as on the 

 third thoracic segment; the third abdominal segment is provided 

 with a black band across its posterior half, the fourth abdominal 

 segment is marked in the middle with two irregularly defined 

 groups of black spöts, which nearly touch each other in the 

 median line; the hind margins of both the fourth and the fifth 

 abdominal segment are black. 



Individuals marked as described above were very scarce 

 among the numerous specimens at hand. The main mäss is 

 made up of quite white specimens, which have only black eye- 

 spots and a small spöt between the antennse. 



Between those two extreme forms there are a number of 

 connecting links, which among other things show that the mark- 

 ings on the thoracic segments and those in the middle of the 

 fourth abdominal segment are the first to disappear, next to them 

 the spöts on the second abdominal segment and the black band 

 along the hind margin of the fourth abdominal segment and 

 finally the cross-bar on the third abdominal segment, which first 

 resolves itself into two lateral spöts. 



The body is densely covered with long club-shaped setfe. 

 These are closest on the posterior part of the head, the ante- 

 rior part of the thorax and the posterior part of the abdomen. 

 The thoracic villosity imparts to the anterior region oftheanimal 

 a brownish tint. 



