228 SUMMAEY OF OURKENT RESEARCHES RELATING TO 



which are both winged and wingless, and their descendants, which are all 

 equipped with wings; (2) the summer phase on some unknown plant, 

 beginning with a wingless, and ending with a winged form ; (3) the autumn 

 phase again on Primus padus, including the sexual forms and the egg 

 from which the ancestor of next year's brood is developed in the following 

 spring. 



Orthezia cataphracta.* — Dr. J. H. List has prepared a monograph of 

 the female of this Coccid, which is found leading a subterranean life in the 

 Alps ; it has generally an oval form, but varies considerably, and there is 

 much difference between young and older examples. It is 3 mm. long, and 

 2 ' 5 mm. broad, while the marsujnum or egg-sack projects 1*5 to 2 mm. 

 backwards. The external integument is wax-like ; there is a dorsal carapace 

 of varying form, the exact relations of which are fully detailed, and there 

 is also a ventral carapace ; the whole has, in living specimens, a white 

 colour, and when magnified, is seen to be superficially striated, the striae 

 running symmetrically on the right and left halves ; it is composed of a body 

 closely resembling wax, and fuses at about 80° C, but in young individuals 

 at 83° C. When this is removed by needles or dissolved off by chloroform, 

 the internal chitinous integument becomes apparent ,• in it areas similar 

 to those of the outer integument are to be detected ; the outer is beset with 

 setae which may attain a length of about 19 /a, are hollow, open to the 

 exterior, and formed of chitin ; under each seta a canal leads to the internal 

 surface of the carapace, and this widens out to a funnel internally ; these 

 canals serve to carry tlie wax-like mass that forms the outer integument. 

 In addition to these setas there are spine-setae, which are also hollow organs, 

 but are closed, and end by a sharp point ; they are placed within small 

 chitinous papillae ; they are in connection with a canal which leads through 

 the integument. Other processes may be called chitinous papillae, and they 

 are best developed in the region of the marsuj)ium. In the hypodermis 

 unicellular glands are to be found, and these are specially abundant on 

 the chitinous funnel of the anus. There are also in the hypodermis some 

 larger cells, which are covered by the dorsal and ventral muscles ; these 

 are surrounded by a distinct membrane, and clearly go to form the adipose 

 tissue. 



The author gives a detailed account of the muscular system, and makes 

 the following observations on the structure of the tissue. If a bundle is 

 observed in 0*5 per cent, salt solution it is seen to have a fine longitudinal 

 striation, and to be of a fibrillar character ; the whole bundle is surrounded 

 by the sarcolemma, which is swollen up at a number of points, where long 

 oval nuclei are to be seen ; between the fibrils there is sarcoplasm, in which 

 nuclei are still to be made out. Sections of muscles hardened in alcohol 

 or sublimate-picric acid allow us to study the composition of the part ; by 

 the action of the hardening material the bundles are somewhat separated 

 from one another. Typical transversely striated muscular bundles are also 

 to be found. 



A thoracic may be distinguished from an abdominal tracheal plexus ; in 

 the former there are tracheal vesicles from each of which a primary trunk 

 arises; the disposition of the secondary branches and of the transverse 

 commissures is described in detail ; the abdominal plexus has seven pairs 

 of stigmatic orifices, but they are much smaller than the two thoracic 

 stigmata. The whole system is completely open, or is on the holopneustic 

 plan of Palmen. 



The mouth-parts are described in detail, and it is striking to observe 



♦ Zeitscbr. f. Wiss. Zool., xlv. (188G) pp. 1-86 (6 pis.). 



