HARDW1CKE' S SCIENCE-GOSSIP. 



25; 



in a house at Gateshead — as recorded by Thos. John 

 Bold, in the "Transactions of the Tyneside Natur- 

 alists' Field Club," 1S57 : " Pulex imperator, 

 Westwood. A friend of mine resident in Gateshead, 

 brought an immense flea, which he had found in his 

 bed, for my examination. Not being able to identify 

 it, I forwarded the creature to J. O. Westwood Esq., 

 by whom it has been described as new, under the 

 above appellation, in a paper recently read before the 

 Linnean Society." Mr. Bold remarks that this flea 

 was at "least ten times the bulk of the common 

 species. One consolation, however, I must 

 not omit to mention, to wit, the fact that he 

 was dead when found, and that, so far, no 

 heirs of the imperial line have turned up to 

 claim the family honours ; let us hope that he 

 was the last of his race." 



keenness of well-bred terriers ; the battle was a 

 drawn one, as after some tugging about the box, the 

 belligerents were accommodated with separate apart- 

 ments. This exhibition of pugnacity was quite a new 

 feature, and afforded considerable amusement. 



The tubes and boxes were kept moderately 

 warm, and the fleas soon deposited their glutinous 

 eggs, averaging a dozen from each individual, 

 irregularly scattered ; the numbers varied from three, 

 the smallest, to twenty-four, the largest, in each 

 batch ; in colour the eggs are of a dingy white,. 



Fig. 179. 



After considerable perseverance, Mr. George 

 Ilarkus has succeeded in maturing a few 

 examples of P. irritans in captivity. It would 

 appear that when fleas are permitted to 

 manage their own affairs, they become far 

 too prolific ; but it has only been by a series 

 of patient and repeated trials, that Mr. Harkus 

 obtained pupa from imprisoned progeny. Brood 

 fleas were of course essential in order to begin ab ovo, 

 these were placed in glass tubes, or glass-topped 

 boxes, a piece of cloth being laid at the bottom for 

 the reception of the eggs. In order to economise 

 space, two egg-laden females were located in one box, 

 but this arrangement was promptly objected to by 

 the captives, who at once became rampant, confront- 

 ing each other like microscopic kangaroos, and 

 instantly seized hold by the head and thorax with the 



Fig- 175- 



in shape a flattened oval. They measure the ^ of 

 an inch in length, and in breadth the J 5 part of an 

 inch. 



With a very fine -,'g immersion objective by 

 Swift & Son, Mr. Harkus was enabled to detect 

 and count a spiral whorl of oval punctures, sur- 

 rounding each end of the ova ; that these were 

 depressions, and not merely surface markings was 

 apparent from an edge view, when the surface 

 presented a serrated aspect. About eighty of these 

 spots pitted the end next the germinal vesicle, 



