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surface is highly arched, but otherwise not altered; the dorsal sur- 
face has the anterior left part flat, showing at the anterior end the 
larval prothoracal spiracles, it is this part which covers the opening 
of the Shell; the posterior right part is arched and bends down on 
the side and shows at the end the two small posterior spiracular 
knobs. Obliquely across the dorsal surface, between the said parts 
stretches a narrow groove caused by the columella of the shell, 
this groove ends behind towards the left in a large, hollow impres- 
sion, likewise caused by the columella. All this gives the puparium 
a very curious aspect, so that it almost looks as if it was made up 
of two combined puparia. 
Ctenulus pectoralis Zett. This species I have bred exclusively 
from Planorbis vortex L. The puparium sits in the shell either 
near the opening or more inwards to nearly å whole circumvolution. 
Like the foregoing it is altered in shape in accordance with its 
place, it is therefore curved, and it is flattened just as the lumen 
in the circumvolutions of the shell; in the anterior part it is really 
flattened dorso-ventrally, but towards the posterior end it is a little 
twisted and therefore here compressed, but somewhat obliquely, so 
that the posterior spiracular knobs are turned towards the concave 
side; for this reason the anterior, flattened part is curved laterally 
while the posterior, compressed part is curved more dorso-ventrally, 
the concave side being the dorsal. It is interesting to see that the 
puparium is always placed in exactly the same way in the shell, 
viz. with its dorsal side and posteriorly the right side towards the 
dorsal surface of the shell, and the puparium is therefore always 
curved in the same direction. 
The third species is new, and I shall therefore here describe it. 
Ctenulus punctatus n. sp. The species is quite similar to pec¬ 
toralis', head, antennæ and palpi of quite the same shape and colour. 
Thorax likewise black, shining, with two a little greyish pruinose, 
less shining stripes, the lateral seam and the whole præsutural de¬ 
pression yellow; sternopleura except the upper margin black and 
metapleura black; for the rest the pleura yellow with a rather well 
defined black spot just below the anterior notopleural bristle; hypo- 
pleura more or less darkened to blackish; sternopleura as in pec- 
ioralis with a bristle at the upper margin. Abdomen and legs as 
in pectoralis, but the fourth joint on front tarsi often darkened. 
