30 SUMMARY OF CURRENT RESEARCHES RELATING TO 



the elytra pertain to the mechanical sense. A scheme is given showing 

 the distribution of the various structures on the alas and elytra, and the 

 minute structure is copiously illustrated. 



Mechanism of Flight in Lamellicorns.* — Fr. Stellwaag has made 

 a very careful study of the detailed adaptations of the meso- and meta- 



thorax, the elytra and the wings in relation to flight. He discusses, for 

 instance, the way in which the elytra are moved into their position 

 during flight and " locked " (serving for steadying), and how in their 

 resting position they are adapted to give the wings the most effective 

 protection. 



Scent-organs in Caddis-flies. f — Bruce F. Cummings calls attention 

 to the enormous development of the palpi of the first pair of maxillae in 

 the male of Sericostoma personatum, a tolerably common caddis-fly in 

 Britain. Unlike the maxillary palpi of the female, which are five-jointed 

 and quite normal, those of the male consist of but a single segment 

 very much enlarged and shaped like a half -moon. These two palpi are 

 placed together and held vertically so as to mask the front of the head. 

 They have received various interpretations, but appear to be definitely 

 odoriferous. 



Scent-organs secreting an attractive odour and confined to the male 

 are known in various Lepidoptera, Coleoptera, and Blattidae, and the 

 case of Sericostoma personatum should be added to the list. Scent- 

 organs are usually on the abdomen or on the thoracic appendages ; 

 their position on the palpi of Sericostoma is unique save for the case of 

 an Indian butterfly, Bertula chalybialis, where well-developed and 

 characteristic scent-organs occur on the labial palpi. 



The author describes the detailed structure of the mouth-parts in 

 Sericostoma personatum, with particular reference to the maxillary palpi. 

 He gives a histological account of the scent-organ, which consists of 

 two sacs and a septum between them, glandular epithelium and scent- 

 hairs rooted in it. 



Tertiary Thysanopteron.J — R. S. Bagnall describes Stenurothrips 

 succineus g. et sp. n. from Baltic amber. It shows affinities with the 

 neotropical genus Heterothrips, and is referred to the family Hetero- 

 thripidas. A very remarkable feature is that the tenth abdominal 

 segment is abnormally produced, and is open ventrally for its entire 

 length. It is longer than the head and prothorax taken together. 

 Bagnall has observed a similar tube-like extension in several forms, 

 notably in Panchsetothrips. 



Gastric Cseca of Heteroptera.§ — H. Glasgow discusses the caeca at 

 the end of the mid-gut in numerous bugs. The caeca contain masses of 

 bacteria of various kinds, " morphologically characteristic for the 



* Zeitschr. wiss. Zool., cviii. (1914) pp. 359-429 (5 pis. and 15 figs.), 

 t Proc. Zool. Soc, 1914, pp. 459-74 (8 figs.). 

 % Geol. Mag., No. 605 (1914) pp. 483-5 (1 pi.). 



§ Biol. Bull., xxvi. (1914) pp. 101-70. See Trans. Amer. Micr. Soc, xxxiii. 

 (1914) pp. 144-5. 



