SCIENCE-GOSSIP. 



325 



writers as a second pair of antennae. The organs 

 •of the month lie about the centre of the carapace, 

 and are of a complex character. The prominent 

 feature is a prehensile tube, having a sharp point. 

 This tube is capable of being sheathed, or moved 

 in any direction by its possessor, the movements 

 being so quick as to be observed only with difS- 

 culty. At the base of this organ will be found 

 two pairs of rudimentary maxillae. On either 

 side of the mouth is a pair of foot-jaws, called pre- 

 hensile feet by Dana and Merrick ; they have five 

 joints and are of a cylindrical shape with three 

 hooks on the terminal joint ; these are partially 

 covered with short spines, and have at their base 

 four chitinous teeth. Baird, in his " Natural 

 History of the British Entomostraca," says these 

 organs have two hooks. 



Below the foot-jaws, and arising from the lower 

 middle portion of the carapace, is the thorax, 

 ■carrying the four pairs of swimming feet before 

 referred to. Each of these has a fleshy base that 

 is pi'olonged into two plvimose branches of about 

 equal length. Under a medium power these are 

 seen to bear others, still more delicate. The 

 stomach commences at the base of the mouth, and 

 branches laterally rmder a large portion of the 

 ■carapace. The abdomen is small, and situated at 

 the lower end of the thorax, where it is terminated 

 by two oval lobes, the use of which I am unable 

 to ascertain. 



In the female, previous to ovipositing, the 

 whole space of the thorax, from the maxillae to 

 the base of the abdomen, is seen to be full of ova, 

 to the number of three hundred or four hundred 

 ■eggs. The surface of the thorax of the females is 

 dotted over with what I took to be pigment cells, 

 bvit on this point I should be glad to have con- 

 firmation, as I noticed the cells to exist only on 

 that sex. 



My observations on a captive female, which I 



had kept in a test glass, showed the ova deposited 

 on the side of the glass, and cemented together in 

 one layer of regular rows ; they were of a pale- 

 yellow colour. The time occupied from the depo- 

 sition of the ova until hatching was twenty-four 

 days. Every egg proved fertile, but I was unable 

 to keep the young alive more than a few days, 

 due dovibtless to the artificial conditions of their 

 surroundings. 



The metamorphosis from young to adult stage 

 is not very marked, except in the development of 

 the swimming-feet, which, in the young, are quite 

 rudimentary, and in the suckers, which are absent 

 in the very young, and do not appear to be 

 developed until several days after birth. In the 

 absence of these suckers, however, the animal is 

 provided with two pairs of bristle-like organs that 

 probably take the place of the swimming-feet, 

 until these are further developed, when they then 

 disappear. The eyes are well in evidence, even in 

 the earliest stage. Some adult specimens which 

 I kept died at the end of fourteen days after sepa- 

 ration from the stickleback. During growth, 

 moulting took place very frequently, the exuviae 

 retaining the form of the parasite in a very 

 perfect manner. This is shown in a specimen I 

 have preserved. Many of the adult Argulus were 

 found to have attached to them numbers of Vorti- 

 cellae, especially in the region of the mouth. 

 I preserved several specimens by mounting in 

 Farrant's medium, and hope at some future time, 

 when material is obtainable, to study further this 

 most interesting parasite. 



The illustrations, representing the ventral 

 aspect of both male and female of A. foliaceus are 

 from photographs I took of specimens under my 

 own observation. 



Paddington Infirmary, 



Harrow Road, London, W. 



LEPIDOPTERA IN SOUTH-EAST ESSEX. 

 Bt F. Gr. Whittle. 



{Continued from page 301.) 



Geometrae. 



f |"^HERE is quite an average number of species 

 -L of the Geometrae to be found in the South- 

 Eastern portion of Essex. I can myself account 

 for 102 different species, and others will doubtless 

 be found in the district. By far the most char- 

 acteristic and interesting moth is our local 

 Phorodesma smaragdaria, once so rare a moth in 

 this covintry. Acidalia ochrata was taken some 

 fifty years ago by the late J. B. Hodgkinson. In 

 recording it, he mentioned the rough hospitality 

 of the people of Prittlewell, who were unused 

 to visits from strangers. This is much the 

 reverse now. 



The following I have myself taken in South- 

 east Essex. 



Uropteryx sambucaria. Southend and Eastwood. 



Epione apiciaria. Prittlewell; not common. 



Bumia luteolata. Everywhere abundant. 



Venilia macularia. Eastwood; common. 



Angerona prunaria. Eastwood; scarce. Mr. 

 Carrington has taken this species among black- 

 thorn on the slopes east of Leigh. 



Metrocampa margaritaria. Southend ; not com- 

 mon. 



Selenia bilunaria. Spring emergence, common. 



Crocallis elinguaria. Benfleet and Eastwood 

 adult larvae common on blackthorn in May. 



