Instrumentation amplifier with capacitor in the feedback network of the first stage
That's not an instrumentation amplifier, it's just a fully differential (input and output) amplifier. It could be the "front half" of an instrumentation amplifier. 

The capacitors form a first order filter, as Tony says, with a cutoff angular frequency of \$1\over{R_1 C_1}\$ = \$1\over{R_2 C_2}\$, assuming it's symmetrical. 

If you want a second order filter, you can put a differential MFB arrangement around the amplifiers.