THE ANIMAL LIFE OF TTTE GROIP. 401 



nine species, all belonp-inp: to one family,'''^ have been determined, six of wliidi 

 are already known from the British Isles. Hnt as tlie largest species '■' is hut 

 a millimeter in length and has only been reported fi-om Kona. on Hawaii. 1h('\- 

 are too small to attract attention from collectors. A,s they occur, li()\vc\cr, it 

 is well to know that the common species •'^" appears to l)e generally distributed 

 throughout the mountains of the group. 



]\Iost of the ticks are small eight-legged creatures, though the number of 

 legs vaiy with age and the mode of life of the parasite. The chicken mite is an 

 example that occurs in Hawaii on poultry; the dog-tick "^^ on the dog: the so- 

 called red spider'^- occurring on cottcm plants, and the true itch mite,*^-' causing 

 an irritation of the skin of liuman beings known as itch, are well-known 

 examples of the species of the order. 



Fleas. 



The ilea is a tiny insect belonging to the order Siplioiiaph ra. and is sug- 

 gestive of the household pests of which Hawaii has its full quota. As has lieen 

 the case with the insects affecting the field, forage and garden plants and our 

 domestic animals, the household pests have practically all been introduced 

 since the islands were discovered. Fleas wei'e among the early arrivals, and 

 may be said to abound in certain localities, especially dry elevated places. Tlie 

 native name (Ukulele) for a "jumping louse" was (nirly applieJ to this 

 tormenter. which is one of the few insects it is not necessary to see in order 

 to identify. AVhile they occur about houses and l)ite the inmates and their 

 pets, the species most commonly captured are the cat-flea or the dog-Hi^a,'^-' 

 though the comou human species'^'' doubtless occurs. 



Plague Carried by Fleas. 



One of the many jjrilliaut medical achieveinents for wliich the closing 

 years of the last century were especially noted, was the discovery that the flea 

 that lives on the common rat is resi)onsil)le for the spread of the di-ead bubonic 

 or black plagu(\ It has been proved over and over again that rats (li<' of this 

 disease and tliat the fleas which infest them and feed on theii- blood di-aw the 

 minute organism causing the disease into their bodies in such a way that they 

 can communicate the plague to other rats and to other animals, amoni: them 

 man. 1)y their bite. Cases are on recoi'd where death from plague has l)een 

 traced to its origin only to fiiul that it came from ilea bites. Fleas usually 

 leave the carcass of a rat that has dunl of plagu(> and at the first o]i]iortunity 

 take u]i their abode on some living animal, as the c;it oi' doi;. From these pets 

 they are easily transfei-red to their mastei's. with the I'esult thai tlieii' bile may 

 convey the miiuite )nieroseopic organism^'' that causes plaiiue in the human 

 body. Flague has appeared on more than one occasion in Hawaii.^" aiul to all 

 appearances has been successfully slampiMl out. Xevertheless. it is well for 



"* Orihatidce. "" Oribrifa nrifnnnis. s" Neotiodes thcli'pfocfiis. ^' Rhipicephaltis xanniiineiix. 



"- Tetraiiychus sp. "•'' Sarfoptt'x xrabei. >** Ctenocpphalus canis = Pule.r ranis. '^^ Pulex irritatis-. 



^^ Bacilus pestcs. *" Xotiibly (hirinK tile winter of 1900. 



