i9u.] 267 



We next wanted to see how the Methoca rendered the formidable 

 beetle-larva hors de combat. The pugnacity of the latter is of course 

 well known, and, as we had opportunity of seeing, it will fight to a finish 

 with any intruder of its own kind. ~No form of animal food comes 

 amiss, and even the large larvae of Balaninus nncum are rapidly disposed 

 of. An excellent account of the life history- of Cicindela campestris 

 may be read in Proc. Ent. Soc. Lond., 1903, p. xv, written by F. Enock, 

 and we need only mention that the full grown larva may be found in 

 vertical cylindrical burrows 2| to 7 ins. deep in sandy soil, the entrance 

 being characterised by the absence of any pile of excavated material 

 (contrast those of Cerceris and other Hymenoptera) . The large 

 shovel-shaped cephalothoracic shield with the peculiarly set mandibles 

 form a neat floor and a deadly trap for any hapless victim to fall on 

 to, or run over, the larva being enabled to stay in any position in the 

 burrow by a double hooked projection from the 5th dorsal segment. 

 When disturbed it does not retreat to the bottom, but usually remains 

 an inch or two from the top, thus facilitating the work of digging it 

 out. 



The question at once presents itself : how does the Methoca get 

 below this head- shield to attack the Cicindela larva in its vulnerable 

 parts ? ; and although we have seen it do so on several occasions, we 

 still only know that it does dodge round somehow or other, and from 

 that moment onward it is all over with the larva. In only one case 

 have we seen the parasite experience real difficulty in accomplishing 

 its purpose, and that was probably an accident ; she apparently slipped 

 down into the hole when the larva was a little below the top, and was 

 caught by a leg in the maudibles of the latter and thrown some two or 

 three inches away. 



The Cicindela larvae readily make fresh burrows in captivity, or 

 will even adopt and adapt artificial ones to their requirements, and 

 after a few experiments, we tried to get them to burrow in sand in 

 glass vessels, in such a way that one wall was formed by the glass 

 through which events might be observed : an ordinary tumbler was 

 found to be much the best for the purpose. 



We were thus able to see that k the Methoca stings its victim 

 several times in the thorax (presumably the thoracic ganglia) 

 paralysing it almost completely, and then deposits a single egg on it. 

 She then proceeds to fill up the burrow with any movable material 

 at hand, even attempting to use Callnna twigs many times her own 

 size, which as often as not she is unable to get into the hole. Extra- 



