SCIENCE- G OSSIF. 



293 



The levers which work them are seen below, and 

 still lower are the palpi, the feeling organs of the 

 stylets. 



Fig. 4 is the proboscis of S. geniculata, treated 

 in the same way, and showing the same organs. 

 Fig. 5 .shows the end of the proboscis of S. geni- 

 culata flattened and moi-e magnified, to show the 



Fig. 4. 



Fig. 5. 



Fig. 4. Proboscis of S. geniculata. Showing the modifications 



of the same parts seen in Fig. 3. 



Fig. 5. Tip of proboscis of S. geniculata. Expanded to show 



what remains of labella and tracheae. 



arrangement of the tracheae. It has before been 

 said that Sifliona is a genus of the large family 

 Muscidae, the larvae of which are mostly reared 

 on excrement or decaying animal matter, but I 

 have reason to believe that S. genieulata lays its 

 eggs on flags or similar plants, and these are 

 hatched out in the following spring ; but up to 

 the present I have not been able to trace the larval 

 stage. 



There is another species of the genus, S. cristaia, 

 which only differs by being much smaller in size, 

 and is properly a variety. It is not so common, 

 but is generally to be met with where the larger 

 form is found. 



90 Belsize Road, London, N. W. 



INSTINCT. 



By E. Dicksox-Brysox, B.A., F.P.S., F.K.As.S. 



{Continued from Vol. VI., page 39.) 



rilHE lion-ant {Myrvieleon), which, by the way, 

 -*- is not an ant, but belongs to another order of 

 insects, begins active life as a p)lump larva. The 

 body of the perfect insect ,is well-formed, long, 

 blackish in colour, with yellow patches. The 

 wings are narrow, long, transparent, and interlaced 

 with a complex nervous system, with irregular 

 patches of white. The larva, on the other hand, 

 is of a dull, dirty grey in colour, has a small flat 

 head, and an enormous abdomen. Its movements 

 are slow and difiicult, and its mouth is furnished 

 with a pair of powerful mandibles with which it 

 seizes its prey. 



Although named the lion-ant, it has not the 

 alarming habits of its homonym, and does not 

 Xjounce upon prey, succeeding rather by patience 

 and cunning. Its victims fall into a trap, but that 

 trap is a masterpiece. Having selected a suit- 

 able, preferably a sandy, place, it proceeds to 

 make a trap. This is generally in the neighbour- 

 hood of an old wall or at the foot of a tree. It 

 begins by tracing a circular trench of faultless 

 regularity and about eight centimetres in diameter, 

 the dimensions being the same for all lion-ants. 

 Entering within the circle, the ant takes up a 

 position opposite the interior edge, and scrapes 

 away the sand with its feet, lifts it on its flattened 

 head, and, imitating the movements of a man's 

 shoulder when heaving a load, pitches it outside 

 the circle. The ant works backwards, and, follow- 

 ing the periphery, continues its work until it has 

 made a complete tour of the circle. It then makes 

 a second within the first, and instead of advancing 

 in the original direction, it takes the opposite. 

 This is probably done to distribute the work equally 

 between the right and left feet. A third trench 

 is made within the second, and the operations are 

 continued until the centre of the circle is reached. 

 Here it adds the final touches to its trap, so as to 

 produce a uniform gradient all round, and to give 

 to the cavity its proper form. When it is complete 

 the greatest depth is about five centimetres. The 

 lion-ant is careful to remove all large-sized grains 

 of sand or soil, which to it are relatively as blocks 

 of sandstone, by throwing them outside the circle, 

 a task requiring enormous strength. Frequently, 

 Sisyphus-like, it may be seen rolling a very large 

 grain up the steep. More fortunate than Sisyphus, 

 however, it abandons the task if these are too 

 many, and sets out in quest of another place. 



The gradient round the interior of the circle is 

 regular and smooth. The finished trap is always 

 of the same form, size, regularity, and p)erfection. 

 Lion-ants all go through the same process, employ 

 the same means, and perform their tasks without 

 previous instruction or the possibility of experience. 

 What is part of the organic structure of the lion- 

 ant, or rather due to that structure, camiot be 

 taught to others. 



We may now consider the tactics of the lion-ant 

 in ambuscade. It is at the bottom of its trap, 

 buried in the sand, allowing part of the head only 

 to be seen, with enormous mandibles projecting, 

 and woe to the imprudent or over-curious insects 

 that wander within the precincts of that dangerous 

 trap. If from the edge of the precipice it throws 

 down an interrogatory glance, a grain of sand is 

 adroitly hurled with prodigious force at its head, 

 striking and stunning it. Before the insect can 

 escape another is hurled against it, and staggering 

 and rolling into the trap, where it is seized, torn to 

 pieces and devoured. The remains are afterwards 

 thrown outside the circle. 



Although the lion-ant constructs its trap so 



